Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
When an Office licence is activated, that becomes permanently linked to the Microsoft account used as a digital licence, there is no native method provided to move the Office licence to another Microsoft account.
1
Try to recover the associated Microsoft account using the steps they provide on this link.
2
If that process is not successful in recovering the associated Microsoft account, try contacting Microsoft support to ask them if it is possible to recover the Office licence, 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