It has to me twice, both with DBZ cels.  It is a 
major pain as they tend to pull bids the last 
day.  eBay has a special feature that allows to 
block bidders, I would use that.  Also, don't 
just block their name, but also their e-mail 
address.  Yes, it is possible for them to change 
it, however, it is one method.

M.