Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
There is no native method provided to remove that new subscription from that account and move it to another account.
Because the new subscription has extended the expiry date on the existing subscription, do not cancel the subscription, you risk loosing the original subscription as well.
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 directly to resolve this problem, 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