Heads up for homeowners who are trying to obtain a loan modification: You better be careful out there.

Ditto for anyone whose loan has been sold or transferred from one lender to another.

These are the most complained-about issues that consumers have with their mortgages, according to the latest tabulation of consumer complaints by the Consumer Financial Protection Bureau (CFPB).

These types of issues pop up again and again, according to the CFPB. In fact, since the agency started accepting complaints in 2011, it has received more mortgage-related gripes than any other kind of financial products -- close to 200,000 of them. Here are some of the most common issues, and tips on how to handle them.

THE PROBLEM: Payment confusion. More than a third of the beefs have to do with just trying to make a payment, which should be a rudimentary task: Stick a check in the envelope the lender sent you, put a stamp on it and put it in the mail. Or, make the payment online. What can be so hard about that?

But the problem isn't on the sender's end; it's on the recipient's. And that's especially true if your lender -- or company that services your loan on behalf of your lender -- transfers your account to another entity. That's when it gets complicated, as many borrowers have found.

According to the CFPB, consumers report "confusion and frustration" about where to make their payments when their loans change hands. They maintain that they do not feel properly informed about the switch. And they complain that their payments often increase unexpectedly.

WHAT TO DO: You should receive a "goodbye" letter from your original lender and a "hello" letter from the new one. If you have any questions whatsoever, get on the horn with the first lender to make sure your loan has indeed been sold.

When you write your first check to the new lender/servicer, make sure you put both account numbers -- the old and new ones -- on the check, and make sure you put down which number belongs to which lender.

About the amount changing without notice: Frequently when a loan changes hands, the new servicer will re-calculate your escrow accounts, and your payment will float up or down according to the new calculation. But again, if you have any questions, call.

THE PROBLEM: Misapplied payments. According to the CFPB, many homeowners say that despite their explicit instructions, their payments are not properly applied. And they grouse that partial payments were sent back to them.

WHAT TO DO: Lenders won't accept partial payments; they say their software programs are not set up that way. So if you can only send part of what you owe in a particular month, call the company and tell them what's up.

The same goes if you feel the need to send the lender special instructions, say, to apply an additional amount to your principal. Call and ask how you should go about this, then call again a week or two after you send the payment to make sure your wishes were carried out.

THE PROBLEM: Loan-mod gridlock. According to the CFPB, financially strapped consumers continue to have big problems when they try to work with their lenders to prevent going into foreclosure. They complain of long delays and a lack of information when applying for a loan modification. And they say that servicers move forward with foreclosure proceedings while their application for a loan mod is under review -- a tactic known as dual-tracking.

WHAT TO DO: This is a tough one, but probably the best advice is to work through an independent housing counselor who knows the ropes better than you. You can find a list of government-approved counselors at www.hud.gov.

As far as dual-tracking is concerned, realize that the servicer is concerned with one thing and one thing only: collecting your money. The lender, on the other hand, would very much like to save the loan. Unfortunately, the two entities, or perhaps the two departments, don't talk to each other.

But under the rules put in place by the CFPB nearly three years ago, servicers are not supposed to start a foreclosure proceeding if a borrower has already submitted a complete application for a loan modification or other alternative to foreclosure, and that application is still pending review. So make sure your application is complete.

Also, to give borrowers reasonable time to submit such applications, servicers cannot make the first notice or filing required for the foreclosure process until you are more than 120 days late. And remember, foreclosure is not just an event; it's a process. How long a process depends on the rules in your state.

Foreclosures are never pretty. Just ask one of the millions of people who were put out of their homes during the housing crises of recent years.

If you want to see what it's like, or what goes on behind the scenes, the recently released movie "99 Homes" will give you an idea.

In my landlording career, I've only been on one eviction when I was left with no choice but to remove a tenant; he hadn't paid rent in several months and wouldn't respond to my appeals. When the sheriff's deputies who served the eviction notice pulled out their weapons before banging on the front door, it gave me a chill down my spine that I'd never anticipated. I quickly backed up -- way up, around the corner -- in case shots were fired.

"99 Homes" will give you that same kind of sinking feeling -- and then some.

It's the tale of an unemployed contractor and single dad named Dennis Nash (played by Andrew Garfield) who loses his home to foreclosure. Out on the street with his young child and widowed mother (Laura Dern), Nash tries to earn the house back by going to work for the shameless realty broker (Michael Shannon) who handled the eviction.

For Nash, the agreement turns out to be more dangerous and brutal than he ever imagined. The movie tumbles deep into the personal side of repossessions, and the bank's agent teaches Nash the legal, and illegal, ins and outs of the foreclosure game.

Another film, due out in December, depicts the housing implosion from the point of view of bankers, who are generally credited with causing the whole mess. Others, too, must share the blame, but "The Big Short" tells the story of how a few Wall Street "outsiders" bet against the housing market and raked in millions when it collapsed.

It's based on "The Big Short: Inside the Doomsday Machine," a nonfiction book by Michael Lewis that spent 28 weeks on the New York Times best-seller list. Lewis is also the author of two other highly regarded books-turned-movies, "Moneyball" and "The Blind Side."

Directed by Will Ferrell's frequent partner-in-comedy, Adam McKay, the movie's cast includes Academy Award winners or nominees Christian Bale, Ryan Gosling, Brad Pitt, Steve Carell and Marisa Tomei. It depicts how banks got greedy by giving out mortgages to people who were not qualified, and how a few traders profited from the banks' "stupidity."

For example, Carell's character goes to a men's club in one scene, where he talks to an exotic dancer who finds out that she can't refinance the loans on her five houses and one condo.

"No one's paying attention," says Gosling's character, who, along with three other small-time financial whizzes, realizes the housing market is on the verge of collapse. They race to cash in on the pending catastrophe -- a tragedy the banking industry, the media and the government either failed to see coming, or didn't want to.

"The whole housing market is propped up on bad loans," says Bale's character. "It will fail."

On the other hand, everyone saw the foreclosure crisis, which unfolded front and center in the media. But most of us were on the sidelines. We had no idea of what it was like to lose our homes, or about the shenanigans that went on behind the scenes as some people profited from others' misery.

The R-rated "99 Homes" tells that story. Director Ramin Bahrani spent months in Florida researching the film. He saw first-hand the so-called "rocket dockets," in which the legal fate of struggling homeowners was sealed in 60 seconds or less. He even went on several evictions, which he called "frightening and horrific things."

The taut drama also describes the dual-tracking system some lenders followed, in which one arm of the bank told owners one thing and another arm told them something else. Many people were trapped in the system and eventually lost their homes.

Garfield, who met with several Florida families who had lost their homes in researching his role, told Yahoo Movies that his own family was nearly foreclosed on when he was a teenager. "A couple of baby steps to the side, and this could have been me," he said.

In the film, Shannon's character, the greedy foreclosure broker Rick Carver, heartlessly evicts Nash with the cops standing at his shoulder. He later tells him, "I didn't evict you. The bank did."

Carver also delivers this chilling homily: "Do you think America gives a rat's (behind) about you or me? America doesn't bail out the losers. America was built by bailing out winners ... by rigging a nation, of the winners, by the winners, for the winners."

People currently in the market for a house caught a break, at least for a few more weeks, when the Federal Reserve recently decided to keep short-term interest rates at their rock-bottom levels.

The Fed's decision doesn't directly dictate mortgage rates, but there is a correlation between the two. So, 30-year loan rates should remain right around 4 percent until the central bank feels that the economy, both at home and globally, is strong enough to handle higher loan costs without cratering.

But there's another time-sensitive factor favoring active buyers right now: According to new research from RealtyTrac's prolific economics department, October is the month to get the best deal on a house. If you can't pull the trigger this month, December, January and February are also good times to buy.

RealtyTrac, a real estate data firm, analyzed more than 32 million single-family and condominium home sales since 2000, and found that during that span, the 2.7 million buyers who closed on their loans in October netted an average sales price that was 2.6 percent below the average estimated full market value.

Not only that, but the best day of the year to buy, according to the analysis, is Oct. 8. Of the 356 days in the year with sufficient sales data, the best bargains occur on Oct. 8, says RealtyTrac, when the buyers' home purchases are 10.8 percent below estimated market value, on average.

If you miss that date, you should do pretty well -- at least statistically -- if you close a week later, on Oct. 15 (an average of 9.1 percent below market value) or Oct. 22 (9.6 percent). And if you can't move that fast, then Nov. 26, Thanksgiving Day this year, will net a price 10.1 percent below full value, and Dec. 31, New Year's Eve, will result in a sale that's 9.6 percent below market.

Since it's tough to match a contract to a specific closing date, especially when two of the best days are holidays this year, let's take a closer look at the best months to buy.

After October, February is the next best month. Buy in February, and the statistics say you should come away with a deal that's 2.4 percent below the estimated market value of your new place.

July, December and January are all also good months to buy, according to RealtyTrac.

Notice that July is the only summer month on the "best months to buy" list. While conventional wisdom has it that spring and summer are typically the best buying seasons, it turns out that winter takes the prize. Surprise, surprise!

The reason: less competition -- on both the buying and selling sides.

O.B. Jacobi, president of Seattle-based Windermere Real Estate, told RealtyTrac that his agents often advise sellers to take their homes off the market until spring for two reasons: the dreary weather in the winter and the significantly shorter days. Those issues make it a challenge to present homes in their best possible light.

But at the same time, Jacobi said, "we tell our buyers that (winter) can be a very opportune time for them, because sellers who keep their homes on the market through the holidays are often motivated to sell. There also are typically fewer buyers in the marketplace, so there is less competition for homes."

Anthony Rael of RE/MAX Alliance in Denver agreed. "Many buyers who may have spent the past six months competing and coming up short may be rewarded in the fall and winter months, as more inventory should provide them with more choices and, hopefully, less competition," said Rael.

For what it's worth, April is the worst month to buy, but the best month to sell. Over the last 15 years, buyers who closed in April paid an average of 1.2 percent above the estimated market value. But of course, that means sellers netted a 1.2 percent premium.

April, by the way, is the only month of the year when sellers have a net gain.

The best day of the week to close is Monday, followed by Friday. Thursday is the pits, apparently.

Of the 5.5 million sales closed on a Monday over the last 15 years, buyers realized an average discount of 2.3 percent. On Friday, the discount based on the sales over that period was 2 percent. On Wednesday, it's 1.4 percent, and on Tuesday, 1.9 percent. On Thursday, the discount was only 1 percent.

For buyers, the bottom line is this: Get on your horse. RealtyTrac's analysis shows that there are definitely better months and days to buy, and the top five days are coming up -- along with four of the top five months.

Sellers, on the other hand, may want to consider waiting until spring if they want top dollar.