You just have to ignore it all. Keep blocking accounts you think are him and don't add any you think might be. Eventually he'll move on.

Document everything he does. Get people to send you screenshots of all the messages so you have a little trove of them.

Warn your friends, family, and close ones about his behaviour. You don't even need to name him, just mention that someone is harassing you through this method.

If he keeps up with it, send him a stern message. If he persists, it may be worth getting free legal council. The most you would get is a very stern scary letter from a lawyer, but that's a REALLY good way to stop people from doing stupid shit.

Ignoring till he meets someone else and leaved you alone is quietest way. Completely ignore. Be oblivious.

That is called harassment and stalking. If you feel you or your boyfriend are in danger you should report it.

Well do you live alone or at home if you live on your own have the locks changed just to be on the safe side . And maybe think about moving to another site like yahoo where it's limited action well not limited but not like fb the setup is different ,

Don't add no friends problem solved