Banning users from FaceBook managed pages
Great article on how to ban a user from your FaceBook page.
I found that a user I was attempting to ban had their privacy set so that unless I was a friend, I was unable to see their like on my managed page. This method outlined below worked perfectly for me (using Chrome)
http://www.thinkcept.com/blog/internet/how-to-block-or-remove-a-facebook-user-from-a-fan-page/#