Is there anyone selling tickets on the 00 1 line?

Yes According to official website who inquires about the train tickets of Zhixing, tickets can be purchased at line 00 1 at the passenger station. Buy tickets at the passenger station, and go to the passenger station in Dongguan or Shenzhen to buy tickets for the 00 1 line in Dongguan. At the passenger station, you can buy tickets directly from the ticket window, or you can use the self-service ticket vending machine.