Can’t select “Some Messenger Friends” under Privacy Settings

I am getting offensive spim from a Hotmail user that I don't know who is not on my contact list. I would certainly like to block that specific person and others of their ilk. However, I don't see any means of doing that even in Messenger 2011 updated to 2012. Furthermore, I'm unable to work around that by preparing a "Limited Access List" which I have done by putting a user from my contact list on the limited access list. (I was unable to put the spimmer on the limited list). I still was unable to select "Some Messenger Friends" even after this, and, yes, the user is listed in the "Limited Access" box. And I sure as **** don't want to accept the spimmer as a contact just in order to subsequently blacklist "it" even if it worked.