Complaints about payday loans have more than doubled in the past two years but the numbers are only 'the tip of the iceberg', the Financial Ombudsman Service (FOS) has revealed.
The most common cause for complaint was that people said they hadn't even taken out the loan. Other problems resulted from poor service and administration, lenders being unwilling to help those who found it difficult to repay the loan, and aggressive debt collecting.
In 2013/2014, the watchdog took on 794 new complaints about payday lending, compared to 296 during 2011/2012.
The FOS's research comes in the wake of last month's announcement that payday lender Wonga is to pay £2.6 million in compensation to customers after it was found to have sent fake letters threatening legal action from made-up law firms.
On a positive note, payday lenders were told to put things right in 63% of cases.
The watchdog said that many people who are struggling to repay payday loans are unaware that they can seek its help if they feel they are not being treated fairly.
"We often hear from people who took out a payday loan as a desperate last resort and blame themselves when the debt starts to spiral out of control," said principal ombudsman Caroline Wayman.
"It's important that people don't feel trapped with nowhere to turn because of the stigma associated with short-term lending."
Last year, debt charity StepChange handled 66,557 cases about payday loans - compared to 36,413 in 2012 - an increase of 82%.
StepChange chief executive Mike O'Conner said: "The payday loan industry has been a problem for many years. Unaffordable lending, the misuse of continuous payments to drain money from customers' accounts, the rolling over of loans and inflating debts with additional charges have been commonplace and damaging.
"We know that payday loans are often a last resort for people who are already in serious financial difficulty. We urge anyone struggling with any form of debt to get free and impartial debt advice at the earliest opportunity."