Problem to activate PD with any major update - no solution so far...

Dear all,
We use several PD Pro licenses and all are running fine except for one user, who always has a problem with any major PD update that it asks for a previous version key. Last month we replaced his MacBook to a new one and again the license server denied the activation due to non-accepted previous license.
We tried all previous licenses which are valid and registered in this account but without success. We completely deleted the application and followed a few suggestions from PD support we got in the past years (like changing or deleting licence.xml and other stuff).

This seems to be a problem which PD support can't solve long time ago and we are unable to use it since more than one month now!
This is really annoying and not acceptable.

Obviously there is a trouble with this user account on PD server but even that I suggested to delete it and provide us a new one which works as expected they haven't provided a solution so far. Is anybody out there who has had a similar trouble and was going to the same bad support and very long response times as we do? Any other solution would be highly appreciated.

Thanks for sharing your experience or solutions.

Best regards
Dieter