I never received the download code for ODST. I bought and played the game when it first came out. You can check when I got my first achievement for the game. I contacted Microsoft Xbox Live support and they told me to post a message in the forum on here. So here is my forum post. I hope someone reads it and sends me an xbox message with a download code.
Hey OP, MS support should have directed you to the Xbox live support forums sky-high maybe they didn’t know about it. XBL support have a dedicated forum set up for things like this. Check the MCC FAQ link in my signature, the section on ODST will outline where to post to get your copy of ODST