Perhaps if you supply lead time, bid amount, and auction # (actual link would be nice) someone might be able to help. It didn't happen to be this evening? Does the snipe have a "status"?
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .