We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
If he threaten to hack you you and only you need to report him to xbox live -because he violated one of the terms and conditions- and if he was the host of the game and simply "rage quit" he didn't violate xbox's terms and conditions by doing so...however
I simply would avoid him and report him for harassment if I were you.