It is really annoying. They do it specifically because it does get a reaction out of you, and that's what you cant feed into. Go to their xbox live profile and report, after reporting go on their profile and block them. Once they are blocked you shouldn't get matched against them or have them on your team (at least this is what ive done and its worked). I think you getting banned, unable to play the game, losing the match/not even having a chance is worse than sitting back in a game and waiting for it to end or letting someone kill you a few times.