Here's what I've done when someone has been tempted to screw me on eBay:
1) Send him an e-mail stating that if you don't hear from him within 24 hours, you will leave SCATHING feedback.
2) If you do hear back from him, state that you expect to receive either your money or the merchandise by fed-ex or you will leave EXTREMELY negative feedback.
3) When the time is up and you don't have either a response or your money or merchandise, leave very harsh feedback, using words like "fraud" and "crook." This usually gets a response.
4) Next contact eBay and attempt to use Safe Harbor (if you qualify) or Square Trade to resolve the issue.
These measures have ALWAYS worked for me.