Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Do you not see the subscription in your Microsoft account at https://account.microsoft.com/services ? Note that you may have more than one account—basically one per Microsoft e-mail. Note that it is possible to use third-party e-mail addresses such as @gmail.com as an alias for a Microsoft account.
If you are sure that the subscription can't be associated with a Microsoft account, you will have to check with third-party sellers such as Google. If you see it in a Google account, that is where you need to cancel the subscription product.