Just try to ignore them.  I got one through ebay 
recently I was so tempted to reply to in anger 
first.  But after I calmed down, it wasn't worth 
getting into an email battle for (and letting 
moron know my real email address).  I just 
forwarded it to ebay's abuse of email contact 
group (like that will do any good, but I hope 
person at least got a warning for their uninvited 
stupidness/rudeness).