Parallels.com upgraded my version 11 to version 12 and my license key no longer works

I had an issue (opened a ticket) with version 11 of your product and you could not fix the issue so you upgraded me to version 12. Am now trying to install my new computer with version 12 and the key that I have (for version 11) no longer works. I receive an invalid license key message. How should I proceed.

Steve Warner