Hi Vance,
Thanks for your question.
For this, you need to create billing support request and since you cannot do that via the portal I will recommend calling the Global support numbers for assistance here: https://support.microsoft.com/en-us/topic/global-customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola