I have never used my personal microsoft account. I use my office account

The $99 charge is most likely from a Microsoft 365 subscription linked to a personal Microsoft account where recurring billing is turned on, or from a different account or store (such as a third‑party retailer or mobile app store).

To resolve this and request a refund:

1. Investigate what the charge is for
   • Go to the Manage your payments page of the Microsoft account dashboard and select Investigate next to the charge:
     • Manage your payments
   • This tool helps identify whether the charge is from:
     • A Microsoft subscription with recurring billing enabled.
     • A purchase made by someone else using the card.
     • A previously declined charge that was retried.
2. Check the correct account and where it was purchased
   • Make sure the sign‑in is with the same personal Microsoft account that was used to buy the subscription, not the work/office account.
   • If the subscription was bought through:
     • Google Play or Apple App Store: cancellation and refund must be handled through their support.
     • A third‑party retailer (for example, Amazon, Best Buy, Harvey Norman): contact that retailer directly to manage billing and refunds.
3. Cancel the subscription to stop future charges
   • Sign in to the Services & subscriptions section of the Microsoft account and cancel or turn off recurring billing for the Microsoft 365 subscription so it does not renew again.
   • If the option to cancel is not visible, follow the troubleshooting steps in Unable to cancel your Microsoft subscription (for example, confirming the correct account, checking billing status, or overdue amounts).
4. Request a refund
   • After cancellation, check if the subscription is eligible for a refund using the guidance in How to get a refund on a Microsoft subscription. Not all cancellations result in a refund, but eligibility can be checked there.
   • If the charge is unrecognized or appears to be a duplicate or mistake, use the same refund article and the investigation tool to support the refund request.
5. If the issue cannot be resolved self‑service
   • If the charge cannot be identified or refunded using the tools above, contact Microsoft Support directly from the Contact Microsoft Support entry point in the refund or cancellation articles and choose a billing/subscription category.
   • If Microsoft and the investigation tool cannot locate the transaction on any Microsoft account, contact the bank or card issuer to dispute the charge as potentially unauthorized.

References:

• How to investigate a billing charge from Microsoft
• Unable to cancel your Microsoft subscription
• How to get a refund on a Microsoft subscription
• Cancel a Microsoft 365 subscription
• Get help with your Microsoft account