Hi Jason Chueh,
Thank you for reaching out to us on the Microsoft Q&A forum.
you may need to collaborate with a billing engineer to ensure that your credits are properly assigned to the correct account. Could you please create a support ticket with the billing team here. They will be able to assist you in resolving this matter efficiently.
For reference, Microsoft 365
Please reach out to us if you have any other queries.
If the information is helpful, please Accept Answer & Upvote so that it would be helpful to other community members.