Can't activate my PRO subscription because I only have upgrade keys

I recently had to rebuild my Mac. I have an active PRO subscription until 1/2018, however, I can't activate the subscription. It keeps telling me that I have entered an upgrade key, and wants the original key. I have emails back to 2009 regarding Parallels, but it appears that all the emails I have are upgrade keys - can you help me with my subscription?

 

We can only find earlier versions of Parallels Desktop under your account. You need to have Parallels Desktop 10/11 to use a Pro version. Please reply to our private message with possible email addresses to check.