who can make a mw3 unbanner here?
There is no way to get unbanned from VAC, there is a way to play after you have been banned but you have to pay a monthly fee. I will not tell you where or how you can search for yourself. And know that using such a method may cause much more far reaching bans than just mw3.
You have to buy a new key on a new account to play on steam again. Or play on one of the private servers