It’s on your shoulders to go to whatever lengths possible to contact the high bidder in your eBay auctions. This should start with the standard post-auction email, of course. If the buyer hasn’t responded within three days, resend your original email with an “URGENT” added to the subject line. You should also amend the message to give the buyer a deadline (two days is good) for his response.
If another two days go by without a response, send a new message informing the buyer that if you don’t receive a response within two days, you’ll be forced to cancel his high bid and report him to eBay.
If a full week goes by and you still haven’t heard from the buyer, you can assume the worst. Which means it’s time to let eBay know about the bum.
Checklist: Dealing with Deadbeat Bidders
Contact the nonpaying bidder
File an Unpaid Item Dispute
Close out the dispute to receive a final value fee credit
Leave negative feedback on the deadbeat bidder
Offer the item in question to the second-highest bidder
or
Relist the item