Change password around 2 hours before you call them, and say you got hacked and you got the account back about 2 hours ago and playing cod mw2 but it says you are banned. They will check and see you changed password around 2 hours before you calls them. It will MAYBE get you unbanned.
(It worked with my real mate)
If you dont find infinityward support phone number, try with www.activision.com, they are a part of cod mw2 too.