I returned a Heston secretarial to Autograph World, but that's about the only return I've ever made. Unfortunately, several of the autographs I discovered were fakes years after the fact I ended up tearing up and throwing away, as the ebay seller was long gone. A couple I probably should have tried to return as the dealer is still in business. None of these purchases was remotely big, maybe $20 - $40 range.
Unfortunately, it's difficult to get your money back. Exposing the sellers of forgeries should be a priority, and trying to sell an item which you know is a forgery should never be an option.
Never resell it. That only hurts the hobby. No one likes be taking advantage of. I purchased one fake. It wasnt for very much money and the seller lived in the UK. I didnt discover it was a fake till months down the road.