Difficulties in upgrading

I’d like to upgrade my Mac 3.2 license to 3.5 as well as purchase a Windows one but in both cases I need the license key.
Unfortunately I cannot find the email with the license key that I had received (I believe I had used my personal email)
I’ve read about the alternative of checking at 2checkout.com… tried that but in that case the order number is requested, I don’t have that either as I think that it was in the email that I don’t find.
I hoped that the license key was present in the Audirvana installation but apparently it’s not
As a result I’m stuck, any advice ?

Thanks for your suggestions!