Citizens Advice Scotland has joined the UK's Financial Ombudsman Service in highlighting how consumers are being "ripped off" by payday credit broking websites, designed to match customers with the best available loans and interest rates - for a fee.
According to Cas, the group has received up to 40% more complaints over "rogue" brokers, which do not make it clear to customers that they are obtaining a loan through a middleman for a fee, rather than from the payday company itself.
Cas said while a lot of credit brokers provided "a legitimate service," some charged hidden fees and refused to provide refunds when challenged.
"It's bad enough that so many people are falling into debt through the actions of some payday lenders - which of course remains a big issue," said Susan McPhee, head of policy at Cas.
"But this trend is something on top of that, which is leading people into financial hardship before they even take out the payday loan. A lot of credit brokers provide a legitimate service - searching the market on your behalf to find a lender who suits your circumstances.
"However, it's clear from our evidence that many brokers are in fact exploiting consumers, taking money off them without their knowledge. Our advice to anyone who is searching online for a payday loan is to be very cautious and read the small print of any website you deal with."
Earlier this month, FoS said it received double the amount of complaints over the last year about credit broking websites.
FoS, which helps resolve issues between customers and financial firms when all other communications and discussions have broken down, said consumers reported their bank accounts being "drained" after opting for a loan through the payday lending broker.
Around 10,000 customers claim that they were misled into thinking that they were signing up for a loan, when entering their bank details, as they were unaware that they were using a broker, rather than a loan company itself.
However, FoS revealed that most of the credit broking websites have since refunded customers the money as soon as it learned the Ombudsman was involved.