Most people who complain to their insurer, bank or building society are dissatisfied with the outcome of their complaint, according to new research by the Financial Services Authority (FSA).
To tackle this problem the FSA has launched a free guide called How to Complain containing tips for consumers to get the best results from their complaints.
FSA head of consumer education services Deborah Arnott said: "It's our job as the independent financial watchdog to make sure that complaints are handled properly.
"That's why we require all financial services firms, like banks and building societies, to have an effective process in place for dealing with their customers' complaints.
"But consumers can also help themselves improve their chances of getting their problems sorted," she added.