Hi,
Sounds like you're getting billed for 100GB of storage for OneDrive, which is 1.99$/month:
Compare OneDrive plans
https://www.microsoft.com/en-us/microsoft-365/onedrive/compare-onedrive-plans?activetab=tab%3aprimaryr1
You can create a support ticket to the Microsoft billing support if you have any more questions, or want assistance regarding the matter, it's free of charge.
How to create an Azure support request
https://learn.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request
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Best regards,
Leon