I'm trying to add my cousin to my friends list, and he's trying to add me.  I received an invite from him and accepted it, and he was on my list for only 5 - 10 seconds, then vanished.  He said he did not get the accepted request, and has re-issued the invite a few times already.  I have done the same--sent invites to him.  We both then deleted each other from our respective friends list and tried to re-add, no success.