Firms that offer help with payment protection insurance claims are facing demands for tighter regulation as they are accused of cashing in on mis-selling practices.
A summit of banks and consumer groups is being held to help raise awareness about the issue as research suggests that a quarter of people are unaware that claims management companies (CMCs) charge a fee.
[Related feature: How to claim back PPI without using a CMC]
According to the survey for Which? and MoneySavingExpert.com, 25% were unaware that CMCs cost them money - usually 25% of their claim plus VAT.
Only half of those questioned knew that using a CMC would be no more successful than making the claim themselves, the groups said.
More than half of those who had used a CMC to get back mis-sold PPI said they would be unlikely to use one again, the research found.
The biggest complaint was about value for money, with 37% of consumers unhappy.
UK banks and other credit card lenders have been compelled to contact potential victims of PPI mis-selling and together the industry faces a bill above £10bn according to estimates.
The mis-selling of PPI, which covers a person's financial liabilities in the event of sickness or redundancy, prompted a wealth of CMCs to launch a flurry of advertising campaigns.
Which? and MoneySavingExpert.com, who are attending a meeting with ministers and representatives of the banks, are launching an advertising campaign aimed at informing the public on how simple it is to make a claim.
The groups believe trust has been lost on the reclaiming process and they blame CMCs.
Martin Lewis, of MoneySavingExpert.com, said: "Sadly PPI has become a cash bonanza for unscrupulous claims companies, who through a series of lies and misdirection are persuading people they are the only option for getting their PPI money back.
"Even I've been texted to be told I'm owed £3,000 PPI - though I've never had the product."
The consumer groups are calling for the CMC industry to be better regulated.
Richard Lloyd, Executive Director of Which? added: "They're saying (the CMCs) come to us and we'll get you more compensation, faster. It's simply not true.
"What people are ending up doing is paying a massive chunk...of their compensation in fees to commercial companies to do something you can do straightforwardly yourself for free."