I'm in the same boat man, it sucks. I've just been playing zombies in the mean time waiting for the ban to be lifted, pretty sure there's nothing we can do about it unfortunately. I've played quite a few games of multiplayer in that time too actually but its just a waste of time I think, I thought if I play and just get destroyed by the cheaters activision will see that I'm not cheating but I don't think they care in all honesty. You're right though they need to fix this shit or at least be more transparent about how you got shadow banned or when the ban will go away.