Can't get the free Halo 3

Greetings support.

I came here to seek help with my problem. I’ve been trying since the 17th of this month to get a free copy of Halo 3 that comes with the Games with Gold thing.
Every time I tried I got an error:

> Sorry
> Your purchase cannot be completed at this time. Please try again.

Any thoughts on my problem? I contacted Microsoft support and they sent me here.
Thanks in advance.

Games for Gold and the Xbox Live Marketplace are run by Xbox Live. If you are having trouble making a purchase, you’ll likely want to call in. There could be an issue with your XBL account causing it not to work.

However once you’ve downloaded the game, if you experience any issues with in-game features, we are here to help you out!