An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
1
On the link below are the steps to cancel the Microsoft 365 subscription.
https://support.microsoft.com/en-us/accounts-billing/subscriptions/cancel-a-microsoft-365-subscription
2
You should then be entitled to a pro-rata refund, on the link below you can check your eligibility for a refund.
I notice you posted to the MacOS forum, on this link it is indicated if you purchased the subscription through Apple using Apple Pay, you will need to contact Apple Support to arrange for the refund.