If you mean PPI i'd advise going direct to your bank regarding any loans overdrafts credit cards anything you have had from them. They will pay your direct and add intrest on the money you paid in. I did it with RBS and got thousands back.
Same with any loan or mortgae from a lender you are still dealing with or have dealt with.
don't go to the people on TV they will take a large cut of your come-back.
it's worth a try. nothing to lose!!