Flaky eBay buyers

[SoCal250]

Do any of you who sell on eBay ever have someone bid on something, win the item, and then ask that the sale be cancelled? It seems to happen every so often but is happening a little more frequently. These flake-out buyers are always overseas. I'm wondering if it's some sort of scam attempt or if they're just too dense to read the listing.

I had one today who placed a bid on an auction several days ago, won the auction, but instead of paying he asked for me to cancel the sale because the shipping was too expensive. Kind of odd since the shipping cost is clearly stated in the listing.