May takes the title as the busiest month for moving in the U.S. From Washington to West Virginia, millions of Americans will be packing up their belongings and heading across town or across the country.

For the most part, moving companies get people’s possessions safely from one spot to another. Unfortunately, some movers make a nerve-racking process even worse. In 2012, the Federal Motor Carrier Safety Administration, which regulates interstate movers, received more than 3,100 complaints from consumers about moving companies. That’s up from nearly 2,900 in 2011. (The nonprofit Better Business Bureau fielded more than 9,300 complaints about movers in 2012.)

Last year, the 10 cities that racked up the highest number of consumer complaints filed with the federal agency were New York; Los Angeles; Chicago; Houston; Las Vegas; Atlanta; Seattle; Orlando, FLSan Antonio; and San Diego.

Some of the most common complaints involved shipments being held hostage; lost, damaged or delayed shipments; movers that aren’t licensed by the federal government; and questionable business practices, such as overcharges. More than 5,800 moving companies are registered with the Federal Motor Carrier Safety Administration.

“Moving is an exciting but hectic time—the last thing families should have to worry about is whether or not their personal belongings will arrive at their new house,” U.S. Transportation Secretary Ray LaHood said in a news release. “By showing consumers how to look out for red flags before they move, we are arming them with information they can use to protect themselves, their move and their memories.”

To ease the pain of moving, the Federal Motor Carrier Safety Administration has launched the “Protect Your Move” campaign. It’s aimed at educating consumers about “red flags” that may indicate a mover isn’t on the up-and-up.

When hiring a mover, here are some of the questions you should ask:

  • Does the mover refuse to make a house call for an estimate?
  • Does the mover offer a much lower estimate than other companies?
  • Does the mover pick up your possessions and then bump up the price?
  • Does the mover try to force you to sign a blank or incomplete document before it delivers your shipment?

“Consumers need to know how to spot the bad movers and feel confident they are selecting a reliable, safe and responsible moving company,” Anne Ferro, administrator of the Federal Motor Carrier Safety Administration, said in a news release. “While the majority of movers are reputable, consumers need to be aware of how to avoid those who are not.”

To avoid movers that are not reputable, visit the Better Business Bureau website or the American Moving & Storage Association website.

“A con artist with just a truck and a website can claim to be a legitimate mover, with unfortunate results for consumers who don’t check out a company in advance,” Linda Bauer Darr, president and CEO of the American Moving & Storage Association, said in a news release. “When it comes to such an important decision, you can save yourself a lot of problems by finding a mover who puts customer service and integrity first.”