One of my foreign credit card worked to buy ticket online. The bus service called to change my pick up address, it was difficult to understand but person on the phone knew enough english to give me the information. The information on app was correct, no problem with pickup. At final dropoff, there was a person taking down addresses for drop off for van shuttle. It will be difficult if you don't know vietnamese. Be aware of what others are doing and use Google translate if needed.

The car runs ok, total time from transfer to Phan Rang office is 6 hours 30 minutes. The detailed itinerary is as follows: 11:30 start transfer from District 5 office to the new BXMD -> 12:30 the car starts departing from the new BXMD -> run on National Highway 1A for about 2pm to Xuan Loc, stop -> then run the high section Speed to Phan Thiet, turn down Highway 1A and go straight to Phan Rang -> arrive at Phan Rang office around 6:00 p.m.