They can certainly do what they please, especially for a gratis service. There is probably a case to sue for damages if this was run commercially, but doesn't

They can certainly do what they please, especially for a gratis service. There is probably a case to sue for damages if this was run commercially, but doesn't sound like @music was. Obviously, for whoever hasn't figured it out yet, Twitter is gone. There is a new service being set up in its wake, but Twitter it ain't.