I have a player that was in our clan. We kicked him out but he keeps coming back. How do you ban a player? We changed the settings to Closed clan and Invite Only clan and we even erased trophies. Nothing is working.
The only explanation is that someone is inviting him. I would recommend demoting everyone but yourself down to member and letting it blow over. Then give back everyone's rank. This should discourage anyone from inviting him again.
It sounds extreme, but it is the only way next to disbanding your clan.
Also, There is no such thing as 'banning' someone from your clan. When you kick them out, they get a message when they try to join saying: You have been banned from this clan. However, they can just join the next day(24 hours). I would recommend changing your clan entry status to invite only too, that way you can reject his request if he was to make one.