He was probably just trying to get you to give him some money back? That would be my guess. If it's stated in your auction that you have a combined shipping policy there is nothing he can do. I see guys charging $4 to ship a card and when I get it, it says $1.29. I don't agree with that but then I shouldn't bid on the items now should I? But I do because it's the only place to get them. It's just the way it's going to work and people should learn to deal with it. You should be fine. There is nothing he can do because ebay would just look at your auction, look at the transaction details(ebay and paypal are pretty much the same company) and make sure you charged him/her accordingly. Once they see that, they will tell that person they should have read the entire auction details before bidding. You will be fine, Brad.