Hello Guys,
We are experiencing a technical issue due to the change to pay mode (instead of free 2 play).
It should be fixed by steam in the next few hours.
Meanwhile if you have installed the Free-to-Play version and want to buy the full version, you need to delete the F2P version before from your steam library.
To do this, go to https://help.steampowered.com/, find VR Paradise (Free-to-Play) game, then select "I want to permanently remove this game from my account"
Once it's done, you will be able to buy VR Paradise paid version.
Sorry for inconvenience.
Cheers