Hey 343i so I bought MCC a while ago about maybe a year or two ago. And it’s telling me I don’t own it I just got off the phone with Microsoft and they told me to contact you.
This isn’t something 343 would be able to help with I’m afraid. You would need to reach out to Xbox Live support if you’re having trouble with game purchases. Generally you can check your download history for games you have purchased, or you can look through your purchase history: https://account.microsoft.com/billing/orders/