Despite me owning and playing The Master Chief Collection since December 18th 2014 I have yet to receive a code for ODST. Is there a direct way to get in contact with a support team about this and resolve the matter?
Your first achievement is the 20th, I’m not sure whether that as a baring on why you didn’t get a code?
As Drunken Haz3 says, your first activity is showing the 20th of December which is past the cut off. If you are due you should be eligible, have a read over the FAQ linked in my signature. There is an xbox support forum you can post on or you can contact Bravo the community manager 