Have you ever sold items at your store to a customer who is never happy no matter how much you offer all the help, ask if they want refunds, but still prefers to hold on to the anger about something.  Well, there is something you can do.  1) Click on the Site Map link in the top right corner of most Ebay pages.  Under the middle column where it says "Selling" click on Block Bidder/Buyer List, 2) Then click the first link and add the Ebay user to my Blocked Bidder/Buyer List, 3) Type in the Ebay user exactly as it is displayed. Then click on submit.  That is all there is to it!