I'm glad that you were able to resolve your issue and thank you for posting your solution so that
others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to accept the answer.
Ask: Renew Non-profit azure grant. We have been re-accepted, and I re-activated it, still it doesn't work
Solution: The issue is resolved. That you resolve the issue by opening a support ticket from my azure portal (search "Help + support" in azure)
The issue was that Microsoft is migrating non-profit billing accounts from an old system (called "MOSP") to a new system (called "MCA"). The issue was that my subscription was under MOSP and they moved it to MCA (I don't think you can do it on your own so that's why you need the support ticket).
To check if you are experiencing the same issue, you can go to Azure, "Cost Management + Billing | Billing scopes" and I had two billing accounts/scopes there (one from MOSP the other one MCA).
Now the sponsorship credit system has moved to "Cost Management" -> "Billing" -> "Payment methods" -> "Azure credits" (the tab takes a while to load in) -> and there is the new balance
If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information.
If you have any other questions, please let me know. Thank you again for your time and patience throughout this issue.
Please don’t forget to Accept Answer and Yes for "was this answer helpful" wherever the information provided helps you, this can be beneficial to other community members.
Thank you.