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, are you able to find two separate subscriptions.
https://account.microsoft.com/services/
2
This forum is just a user to user forum, no-one here has any account access, if you are sure no-one else has access to your banking details, 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.