@your ban on alterIWNET:
If you got banned without cheating (hosting MODS for example), you can try to appeal your ban. Go to the alteriwnet website for that.
If you cheated (aimbot, wallhack, rape mod, host only advantages, etc..) you most likely, and rightfully so, won't get unbanned.
If you have a dynamic IP, you can try the unban tutorial posted here somewhere, which changes your XUID, tho many people report it not to be working.
@Buying a cracked game: lol, that's not very smart. You can't do fuckall about it. Unless you know the person you bought it from, but if it was online, you're shit out of luck. Perhaps if you bought it through Ebay or something you can file a complaint.