I had one like that too. But the guy got my Spider Sense tingling almost immediately after the auction ended so I was hyper-vigilant about keeping all communications (come to think of it, maybe the price was a little too good to be true to begin with, it was a motherboard going at 2/3 the going rate from china and half from USA). There was a window of 3 days for the return and when I looked at his ENTIRE feedback history it appeared that he had sold several items that were clearly misrepresented. I really got suspicious because I paid extra for 2-3 days priority mail and he hadn't even sent the thing a week later. When it got to my door I took pics before even opening the box and was unsurprised by the condition of the board inside. That one was a huge pain because when I filed the dispute the guy even tried to claim he never received the item in return and claimed a different address than the one handwritten on the package. I actually did some research via public record to find that address in the name of someone who happened to have the same last name as his wife which added some credence to my claim along with the delivery confirmation and photos of the mailing reciept, which I posted on a flickr page with photos of the obviously (and poorly) hand refurbished board along with each and every communication received from him which included profanity and threats of not granting a refund unless I lifted the hold on the Paypal funds. What an ass.
Fortunately. though I quite expected it to drag on for a month, my entire cost was refunded in two days via paypal, It did cost me the 11 bucks or so to ship back, but I hate when people try to be deceptive and sucker somebody out of even a little bit of money. since sometimes its all they have.
For the most part, even though its a pain, I do gather that the claim process favors buyers over sellers. though. If you have even a little bit of evidence to back up a claim, you will probably win. Then again. I don't know how much of the complaining is done by less than careful sellers either.