Harrassment is against eBay policy.  I suggest you 
forward the emails he sent you (along with the page 
source for the email) to eBay and let them deal 
with him.   
Also, make sure that you are not breaking eBay 
rules either, because charging fees for credit card 
services is against their policy, whether you post 
in your auction or in your congrats emails.  The 
way to get around that is to charge a handling fee 
to everyone (about a dollar or two over and above 
the postage/insurance cost).  If you have any left 
over money from the handling fee, put it towards 
gas for your car to drive to the post office and 
the time you spend to pack everything.