Hey Alex!
Nice to meet you! I'm Darhyl, an Independent Advisor. I'm sorry you are experiencing this on Microsoft Rewards.
Just a gentle reminder that we are only Microsoft users just like you here in the community. We are not Microsoft employees and we do not have tools to access any Microsoft System.
Based on your description, this can only mean that the Robux codes are temporarily out of stock. You will need to wait for the Rewards team to replenish the codes.
In the meantime, I would recommend saving your rewards points and checking the Rewards Store from time to time.
If you feel the need to contact Microsoft Rewards Support, you may submit your ticket through the link below:
https://rewards.bing.com/support
Thank you for your kindness and understanding! Please let me know if you need anything else.
Best regards,
Darhyl
I tried to get my robux gift card today because I have saved up 1,500 points for 100 robux I found it gone I thought it was because my account was acting strange I tried a different account but same thing. I hope it will come back in January.