You can use our User Messaging Center to try to get in touch with seller/bidder. Go to the Member Center and click on "Forum Control Panel". From your control panel, you can send private mail. Use this if emails are bouncing back that you have been sending to seller/winner. They may not know their emails are bouncing.

If it has been at least a week since the auction ended and you have tried the above method:

• If you are the seller of the item, you can contact the next-highest bidder to see if he/she is still interested in the item. After a week of trying to get in touch with the original high bidder, it's perfectly acceptable to move on, even if extraordinary circumstances have kept the bidder from responding.
• If you are the high bidder of the item, your obligation to purchase the item ends when the seller cannot be reached.

If you have tried email and the message center, you've done your best. In any case, you can use the feedback system to leave either neutral or negative feedback about the user, to help other users decide who to do business with.