xbox gift card

I have a gift card that we purchased and it says that it was redeemed. The card was purchased on Amazon and they do not offer support since they do not have internal access to Microsoft products. When it takies me to xbox.com to access the code it says
that the code was redeemed. I( am spending a ridiculous amount of time trying to navigate this issue for my son. He and two other friends are having the same issue where the card says that it was redeemed. It also does not show up on my order history through
Microsoft. What is the issue here????????

:)