Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi,
Did you purchase the subscription on your Mac through the Apple App Store?
If yes, your subscription is managed by Apple. I recommend contacting Apple Support to see if they can help you cancel the subscription associated with your Apple ID.
If they are unable to cancel it because you no longer have access to your Microsoft account, your last resort is to contact your bank or card issuer to stop future recurring charges.