Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
1
Log into any Microsoft account you may have on this link to check the expiry date on the Microsoft 365 subscription and to check if you have two separate subscriptions.
https://account.microsoft.com/services/
Then open Word on your PC, go to File - Account, on that link you will see the Email address of the Microsoft account you are using for Office.
If you find two separate subscriptions, on the account with the second subscription, select Manage on the subscription and you can cancel it form there, ensuring you do not cancel the subscription on the account listed in Word.
2
If you are unable to find two separate subscriptions, using any Microsoft account you may have, try using the steps they provide on this link to find out what that second payment was for.
Then use the steps they provide on this link to cancel whatever that second payment was for and get a refund.
2
If you are still unable to resolve that second payment problem, 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