Well here goes nothing,
My friend recieved a 12 month xbl subscription from his aunt about 2 years ago. He couldn't use it because he didn't have a router, or a second eathernet port on his PC. About a week ago he brought it to my house (since I have a router) and we were going to set up an account for him. When we opened up the box, he said there was no 12 month code in the box. I talked to Xbox Support via their 24 hour instant support. They told me that the issue could not be resolved by them it had to be resolved by the store where the 12 month was bought. My friend asked his aunt and she said she bought it at EB games. We told the guy at EB about this problem and he asked to see the box. He checked the box and then talked to his manager/boss. Well we ended up with a 12 month card that the manager took out of another box. When we got back to my house, my dumb ass friend then went to play criminson skys, and out poped a 12 month. He didn't realise that the 12 month is in the game case, and not in the actual box. So we ended up with 2 12 months. Hope this helps some poor people.