I am trying to transfer a visio 2013 standard diskless package from one pc to another for a smb customer. the ms account used to redeem the package is no longer in existence according to the office myaccount site. There was a stick-it note with the freshly created ms account used to install originally left in the box containing the product key. the client is no longer employed by the company (it's not a case of the ex-employee changing his password FYI). I supplied the software and installed it back in 2013 by the way. I have the date when I delivered the package which may not be the redemption date.
How do we unlock the product key?