Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
You can cancel the subscription using the steps provided on this link and while there, disable recurring billing on the subscription to ensure no further payments are taken from your account.
Then you can use the steps on this link to check your eligibility for a refund.
If you experience any problems with that process, this forum is just a user to user forum, no-one here has any account access, you will need to contact Microsoft Support directly, try using this method to contact their support.
Go to this link: https://support.microsoft.com/contactus
Select Microsoft 365
Click 'Get Home Support'.
In the box provided, type billing.
Press Enter, then on the next page, scroll down and click 'Sign in to Contact Support'.
Navigate to Microsoft 365 and Office - Manage my Subscription.
Select the 'Chat with support agent in web browser' option