To cancel subscription on Windows:

1. Go to Services & subscriptions https://account.microsoft.com/services. You might be asked to sign in.

2. Find the subscription and select Payment & billing > Cancel. If you don't see your subscription, make sure you are signed in to the correct Microsoft account for that subscription.

3. Select Confirm cancellation. Check your inbox for a confirmation email.

For more details please visit Microsoft Support page 

Please contact us if we can be of any further help to you. 
Best regards,