Eon method

Your just gonna call Microsoft Support, 1 (800) 642-7676, and give an excuse about how you did not receive the eon code you ordered, so examples, some I've used, are bellow, feel free to make your own excuse.

"Hi, I just bought my son an xbox with the eon code bundle and I decided to download all the games and redeem all the codes so he can play his new xbox when he gets home" - pretend how your a dad that bought a eon code bundle xbox and keep your story going to make it more believable.

"Hello, I just bought a controller that said it had a Eon code in it but when I opened the box there was just the controller, nothing else."

And there are many more excuses/stories but here are 2 I've used multiple times, the first one is really good.

FAULTS:

-They might ask you for a receipt, just make up a story about how you lost it or can't read it.
-They representative may be a dick, just hang up and try again on a different rep.

Those are the only major faults I have ran into thus far.

I hope this method works for you as much as it has for me! Good Luck out there and thanks for purchasing!