Starting from buying train tickets, several days' ticket refund is not subject to a service charge.

You can check the announcement of 12306. The time is not calculated from the time you buy the ticket, but from the driving time forward. The refund fees are different in different time periods.
You can check the announcement of 12306. The time is not calculated from the time you buy the ticket, but from the driving time forward. The refund fees are different in different time periods.