I guess I'm lucky, In the four years I've been on Ebay I've only had a handlful of bad experiences. This is in a total of more than 1000 transactions, both business and personal. The few bad expereinces have been false bidding to drive up prices or those who have bid on an item and then don't pay. I've always received what I have bid on and won. If you didn't I would suggest letting ebay know, they have insurance against this and can assist you in getting a partial if not complete refund.
Kev
Kev