Rams, even in the principal's office, they would not let him take the call when she CALLED BACK and they know very clear what the situation was and, according to their statement, were sympathetic and trying to work a way for her to be able to call him at school.
It doesn't seem like they were trying to work out a way if they wouldn't let him even take the SECOND call.
He had probably torqued them off so badly by that juncture that they were in no humor to do anything for him. But that's not the point. He flouted the rules and directed vulgarity; perhaps even violence, toward his teachers. That's enough to get him a suspension in my book, even if it turns out that the teacher behaved inappropriately.