Thanks for the Steam Publish Team. They have helped to turn the game into a free game. And they said that they will enable users to self-refund the game.
Someone who have bought Deadly Hunter VR said that he can't get refund. I have sent a email to the Steam Publish Team to get help. If there are any news, I will notice asap.
By the way, If the people who have bought Deadly Hunter VR can not get refund, I will send a key to you when I release the next VR game. I won't let the people who like the game come to grief.