Emails from "Blocked List " Appearing in Inbox

I'm running NIS 2010 and Outlook 2003 on a Windows XP machine.

 

When I click "this is spam" on email messages, they are moved to my "blocked list," but messages from these senders keep showing up in my inbox days later.

 

I have verified that the offending addresses are on my blocked list and that the new incoming messages to my inbox are from the SAME EMAIL ADDRESSES  (not just the same "from" name).

 

This is beyond frustrating. Please help if you have a solution. Thanks!!