parallels upgrade

I just purchased Parallels 20 for Mac, upgrading from Parallels 18 permanent license. Paid $69.99. NOW they want another $69.99 (or more) to upgrade my Parallels 18 so it will upgrade to Parallels 20. Can't even email customer support without paying another $30!!! I use Parallels rarely, only...

Hello, I bought the upgrade to Parallels 15 for MAC. i am unable to register my product using the upgrade key. The reason i am getting is that. the previous key is not valid! Please advise Best, Roy