Go to the Site Map (link at the bottom of this and most ebay.com pages) Sell Section (use the shortcut at the top--it's a long scroll down) and you'll find the link to that (Blocked Bidder/Buyer List) and several other useful seller tools. Before you click through from the instruction page ("Bidder Management") to the actual BB/BL, scroll down and set your Buyer Requirements if you haven't already done so and make sure you've checked the box to block questions from blocked buyers (not 100% effective but helps).
