Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello
I am afraid your best option is to have it canceled at your bank/credit card company.
Since it was purchased through third party, Microsoft doesn't have anyway to manage your billing /subscription.
Microsoft explains it here: https://support.microsoft.com/en-us/account-billing/manage-your-microsoft-365-subscription-purchased-through-a-third-party-44749f45-4c0b-5d41-a73f-7634b8d2a763