Go to Activision Support and I'm pretty sure there is a way to generate a support ticket.
However, bans are almost never reviewed. There is no discussing the bans with the person that was banned. And they especially do not like folks coming to the forums to discuss bans. This thread will end up locked and you'll get a warning not to post questions about bans in the forums again.
I will tell you this - it does not matter whether or not "YOU" did anything wrong. Your account was used in a way that violates the rules to a degree that is bannable. You boosted, benefited from a hacked lobby, used language against someone in a very offensive way, participated in some online scheme, etc, etc.