Invalid product key

Hi.

As I got myself a 4k monitor alongside my regular 1920x1080 monitor, my fences has been bugging when I enter games and come back to the desktop. I looked into the settings and I think I fixed it, maybe, however one fence got so large that I can't select it, and I can't get a hold of the upper edge for me to shrink and delete it. I decided that heck, I'll just uninstall reinstall the whole thing, right?

Before I do that, I wanted to make sure that I still have a file to install from, so I come here and I find out that my account no longer exists. So I think okay, maybe I did not make one, so I'll register my mail and create an account, turns out my email account is invalid for account creation some damn how? Anyways, most people have multiple mails so I used another one to get here to post, about my concern that I found when I decided to register my product key - it is invalid. I might have used it when I installed fences a year back or so but I really can't recall.

I'd like to validate my product-key for fences so I can keep using it. I still have the original mail with the reciept from buying the product.

Sincerely, a fences user.