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Identity theft was the fastest-growing consumer complaint in 2014, according to a joint annual report by the Consumer Federation of America and North American Consumer Protection Investigators. The list is based on more than 280,000 claims made to 37 consumer-protection agencies in 21 states last year.

Recent, large-scale data breaches at major retailers are at least partly to blame for the rapid rise of identity theft complaints. (It also was the top consumer gripe handled by the Federal Trade Commission last year, making up 13% of all complaints.)

Read next: 10 Funniest & Most Creative Consumer Complaints Ever

Consumer agencies say that stealing someone's identity to claim their tax refunds, in particular, is a growing problem. "Refund fraud caused by identity theft is one of the biggest challenges facing the IRS," says the agency, which has 3,000 employees working on tax-related identity theft.

The 37 agencies the two groups canvassed deemed debt collection the worst category overall for consumer complaints, based on a combination of complaint frequency, the dollar amounts involved and how severely vulnerable populations were affected. In some cases, people were hounded to pay debts that weren't theirs.

"They make harassing phone calls or send threatening emails to scare consumers... to satisfy a loan that doesn’t exist," the groups' report says. Other victims who filed complaints with state and local agencies said they were subject to abusive language and other illegal practices from debt collectors, such as threatening them with arrest or calling late at night. (By law, these agencies aren't supposed to call after 9 p.m.)

Some complaint categories are perennial hot buttons. As in 2013, automotive-related issues were the most frequently reported to protection agencies last year, including, "misrepresentations in advertising or sales of new and used cars, lemons, faulty repairs, leasing and towing disputes," the CFA says. Other mainstays in terms of generating complaints include telemarketing robocalls, construction and home improvement firms, landlord-tenant disputes and shady retail practices like false advertising or issues with gift cards or coupons.

There were plenty of new contenders causing major consumer headaches last year, too. Consumer protection agencies reported an influx of complaints about student loan repayment or consolidation scams, and businesses refusing to honor customer agreements such as rebates, gift certificates and contracts after changing hands, sometimes even though the businesses retained their old names.

"A good recent example is gyms that have closed and be reopened by other, larger corporations," says Ethel Newlin of the San Francisco District Attorney's office. In some cases, she says, "Consumers were left with worthless contracts for the rest of the term they had already paid for."

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