Previous activation key not working for Parallels 12 upgrade

Hi, I really need some help. I've purchased the Parallels 12 upgrade however my previous version key isn't working. After successfully entering my upgrade key - I purchased a few days ago - it still won't let me activate it. The problem is, it can't register my previous version key although the key is recognisable with a green tick (please see attached file) it still doesn't let me get past the activation step.

I've had to start a 14 day trial because it still won't let me activate it. Please, please can anyone help?

 

Please check your private message and respond. We'll continue from there.

 

Hello ErnieR2,
As per your request in the private conversation, we have initiated refund for the upgrade and suggest you to buy the full version.