can someone please help me with upgrade problems??

Hi, I'm new to the forum and would greatly appreciate any help anyone might offer...
I was way behind on updates and had Mac OSX Mountain Lion and Parallels 8 for desktop. I upgraded to El Capitan yesterday with no problems. Downloaded and tried to install the Parallels upgrade to 11, not realizing you had to be on at least 9, so of course, it wouldn't take my product keys. So I tried to download 9, thinking I could upgrade to 9 and then 11. Nine appears to be a free DMG, and then when installing, it gets to the point of asking me for a product key, which I don't have. It won't take my 8 or 7 keys either...
Anyone have any ideas? Because now it seems I have nothing! When I try to go to the previous icon I had, it takes me to 11 activation screen...
I guess I could reinstall 7 from disc and then my 8 upgrade?? I'm fine with buying the $79 full 11 version, but I'm wondering if I can get credit for the 49.99 upgrade to 11 I couldn't use........ ???? Thanks so much for anyone's advice!!!

 

Follow-up.... duh... I just realized going back to 7/8 is not an option now with El Capitan So really help, please!! I work on a program that only works on Windows and have to get back to work Tuesday... the support ticket page isn't taking my support number either!!

 

Hi Jennifer,
Parallels Desktop 11 can be upgraded from version 9 and 10 only. Since you are using Parallels Desktop 8 currently, you are not eligible for the upgrade. In this case you will have to purchase the full version. Please check your private message.