Sorry to hear about the weasely bidder. I just had 
someone flake out on one of my auctions too. -_-# 
Anyways, you can use this link to block the bidder 
from being able to bid on any of your auctions:

http://cgi3.ebay.com/aw-cgi/eBayISAPI.dll?bidderbl
ocklogin

good luck!
nessa