What should you do if you are in a transaction with someone on eBay and you've run into a problem? If you've already tried sending an e-mail, you need to get more contact information. Remember back when you registered and eBay asked for a phone number? eBay keeps this information for times like this.
To get an eBay member's phone number, go to Find Contact Information on the Advanced Search: Members: Find Contact Information link. Fill out the Contact Info form by entering the seller's (or buyer's - if you are the seller) user ID and the item number of the transaction. Then click the Search button. If all the information is correct, you automatically see a request-confirmation page and eBay generates an e-mail message to both you and the other user.
eBay's e-mail message includes the seller's user ID, name, company, city, state, and country of residence, as well as the seller's phone number and date of initial registration. eBay sends this same information about you to the user you want to get in touch with. Most eBay members jump to attention when they receive this e-mail from eBay and get the ball rolling to complete the transaction (or solve a problem).
You can find more on this subject - and lots more in eBay For Dummies, 6th Edition. (Amazon link)