I tried following those directions, but when I logged in, there were no keys or downloads visible, only the buy button. The recovery form said that my key was not recognized.

I purchased cubik studio pro in 2015 (when you were using BDCraft.net/cubik and not cubik.studio), and was using it without paying much attention to updates. I still have the email and my serial key, but I can't find anywhere to enter it on the site, even after logging in it just gives the option to ...