How you book the jiuzhaigou tickets in the end? Via 3rd party?
I planning to visit jiuzhaigou on my own too.
For the more inexperienced with China apps, booking via trip.com is safer. Pay $5 to them for service.
*if need to cancel, then cancel via trip.com to get the refund. Think if book via official rail app, if cancel then need to go to the station to get refund.
*trip.com charges fee to help to cancel (remember reading a massage to either go station to get refund or they can get their people to go station to get refund with a service fee). Can't remember how much is the service fee but I got my fee waived coz of my whatever tier membership with them (that's why I have no records of the service fee).