Hello,
Thank you for providing those additional details and what you’re trying to do! Instead of the Live key, you’ll want to use a Stage Sandbox Key as the Stage Sandbox is what our moderation team uses for testing. This will ensure you’re mirroring the test environment as much as possible.
However, I’m still concerned when you say that the keys didn’t work. Were they not able to redeem the keys to their account? If it was redeemed, was there an error when attempting to download the game? Any additional details about your experience would be greatly appreciated!