And no matter what account you’re talking about, take a quick moment to think if there’s anything important that uses the same username or email address and the same or a very similar password, like maybe the mail account itself, a banking site, Paypal, or indeed Steam if that isn’t what you mean. (Or do you mean another XBox live account?) Change those passwords immediately!
Good luck getting it back.
(Also, wrong topic, but in this case we’ll forgive you.)