Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Please sign in at https://account.microsoft.com/services using every Microsoft account you may have used, as the two Microsoft 365 subscriptions could be registered under different email addresses.
Check the charges at https://account.microsoft.com/billing/orders, then turn off recurring billing for the unwanted subscription.
If either subscription was purchased through Apple, Google or another retailer, the refund must be requested from that seller.