I paid to help support and have a simple question. What's the Steam Key for? I claimed it but don't see an entry or an option to redeem the key on Steam, is this for future use?
If you bought the regular version and you want to upgrade to premium, I think there are a couple of ways. One other user in the comments bought premium this way. If you want, you can return the regular version by telling support and get it as premium again. If they don't refund your money, I can email you the game in exchange for the money you paid for the premium version.