Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
1
Using any Microsoft account you may have, if you are sure no-one else has access to your banking details, try using the steps they provide on this link to find out what that payment was for.
2
If you are unable to locate what that payment is for, rather than cancelling the card, are you unable to get your bank to cancel the direct debit for the Microsoft payment.
2
If you are still unable to resolve that payment problem, this forum is just a user to user forum, for account security and to protect users no-one here has any account access, you will need to contact Microsoft Support again, 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