They should sue them for defamation of character since they are saying the documents are hacked. The should sue for breach of contract because Twitter isn't following their own terms of service. Proving damages wouldn't be a problem since they are blocking traffic they would normally be getting on a viral story and damaging their reputation. The New York post should make an example of them and they have the perfect opportunity to do it. If they get lucky they might even be able to get an injunction to force twitter to unblock their account.