Just tried to sell my first bitcoins on ebay, and the auction went really well with lots of action and a good final price, but now the buyer will not pay for the bitcoins he won!
Anyone else dealing with this?
It seems like my buyer at least is using ebay to buy bitcoin options at no risk. Since the tank, he has had no reason to pay up

That seems like only a small problem...
The buyer may even pay, but they can force a
chargeback down your throat all the way to your
credit card and your
bank-account (if you have those linked) for upto
6 months after you got paid. I once got scammed this way and lost 200% on what i sold (the virtual goods i had sent + the chargeback)
Easy solution, stop using them.