Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
You will have to sign in to your account and cancel the subscription product. Go to https://account.microsoft.com/services .
The "rules" for refunds are discussed in the support article at https://support.microsoft.com/account-billing/how-to-get-a-refund-on-a-microsoft-subscription-67dca30b-b323-44d5-acc2-e02f9902c472 .