Can the Jianshui train ticket be refunded after booking?

You have to read the rules on the reservation page. If it says non-refundable, then it is non-refundable. If you buy the ticket on the spot, you have to ask the on-site staff.

You can call the ticket office and ask.

It seems impossible, we bought tickets on the spot.

It should not be possible, please check with the innkeeper for details