You may contact ebay service again and seek their advice for this situation. Based on my experience, their service is good(but not nessarily sovle your problem).
How did the buyer pay you first time(paypal or personal check)? If buyer
has paypal account and refuse to use it, then something is very suspecious. What's the buyer reputation(feedback)?
Maybe buyer will pay you a little bit later. He wants to sure the first check(assuming he sent to you ) will not be cashed.
Good luck!