When Black Ops 2 Bans, it's either an Account Ban or a Mac Ban. So if you're saying that it's not an account ban, then I recommend trying to change your Mac Address. You may have not changed it correctly, because i've never experienced a problem like this. A lot of people have been getting banned from PSN from some reason as well, if changing your Console ID won't solve the problem, then i'm not sure what the solution to your problem could be...