No.

no.

Valve has to set a reasonable limit somewhere because otherwise they would have to pay back the money out of their own pocket since they have to pay the game dev/publisher sonetime.

You can try a manual refund, but if they say no, it's final.

https://psteamhelp.yuanyoumao.com -> login -> scroll down -> enter the name of the game or DLC in question -> view receipt -> I have a question about this purchase

Write your inquiry thoroughly and in a formal and courteous way, explaining the issues you face, the request for a refund and to where you wish to refund (wallet or the payment method used).