anda can block MESSAGES from them and anda can prevent them from posting on your dinding if anda aren't a peminat of them. I don't think anda can block them from seeing anda though. But,if he is stalking anda atau bothering anda then anda should tell one of the admins to get him banned/suspended atau even IP banned where he CAN'T make another account on the device he is using. (Unless he gets another one and goes through that.)