Wondering why I didn’t seem to get the code, I looked in every email that was ever associated with XBL. After finding nothing in any inbox, trash or spam folder, I decided to go to my Gmail account and Click “All Mail”. To my surprise, there it was, titled “Here is your free gift from Xbox” with a subtitle “Thanks for being an Xbox LIVE member. You’ve earned a free gift. Just follow the instructions below, and you can download it immediately.*”
It mentioned nothing about Halo, so I may have sent it to Archive, but even if it just happened to be hidden there somehow, I just wanted to alert people so that they may look there.