Originally Posted by visortgw
Try looking at Options > Security Options > Firewall (may be slightly different depending on OS...) to set Block Incoming Messages. While you cannot specify address to block, you can block all SMS or MMS Except messages from Contacts or Specific addresses (i.e., white list as opposed to blacklist).
Hope this helps...
Man that totally worked. Set it to block all SMS except from people in my contacts, then I just took her off my contact list. Thank you, saved the day on that one.