Roblox Giftcard promised virtual item if bought from microsoft rewards but I didnt get the...

Contrary to the above, as you redeemed the card from Microsoft Rewards, then you need to contact Rewards, not general support:

Microsoft rewards Support

how do I get the code for microsoft guftcard i bought it from ms rewards and i want to buy robux and when i go to roblox to purshes robux with my giftcard it doesnt show method for ms giftcard could you please help

thank you

Yes you already explained to me that the suspension on a microsoft rewards account wont affect my roblox but if I use 2 microsoft accounts and get giftcards on the 2 accounts and use both of the giftcards on my main roblox account what happens?

I bought a roblox add-on (400 robux) thanks to microsoft rewards, i recieved the email of the payment but didn't get any code (giftcard code i suppose) so i can't reedem it. What should I do?

Punish your boy and tell him to NEVER make purchases again without allowance.. And I doubt you can get the money back because your son would've payed for the ROBLOX virtual currency known as robux and he as probably bought clothing and game passes with these
robux so nor Microsoft or the ROBLOX team will be able to get the robux back because they are unable to take the bought items off his ROBLOX account. Also change the settings on your Xbox to make it require a passkey or your password when making a purchase!