Bought a botched copy of Master Chief Collection yet after months and months of hassle I still have no ODST code, whats the easiest method of solving this?
You had to have played MCC before December 19th of last year. Looking at your service record it doesn’t show you getting your first achievement until the 20th, so your gamertag was likely never included in the list as it missed the cut-off. You can try posting over on the Xbox Live support forums - see the MCC FAQ link in my signature / stickied at the top of this forum for details - but they will likely tell you the same thing
I’m able to prove I played it on the 18th, they can’t limit it by acheivements