You just have to be patient
I had my test booked for the 30th July and had been told by my instructor that she was confident in me moving it forward and was recommended this app it did take a while for me to be able tonuse it as they wouldn't allow new members until they had dealt with the backlog but I managed to login and paid for premium with autobook enabled on the dates I had chosen it took a while and I had lost hope and was had came to terms I wasn't having my test any earlier until I have recieved an email that my test had been rebooked 2 weeks earlier I knkw it's not much of a difference but it means the app does work you just have to be patient and hope someone cancels and you can get there time/date i would definitely recommend this app