Clicks Alberton city!!! Doesnt want to do their work

My husband and I have booked an appointment with Clicks in Alberton city for our 2nd vaccines. When we got there the security lady said that they "cut" the line for vaccinations. When the manager came to tell us that we have to go home, I told him that we have booked an appointment then he said no they do not do bookings the goverment does them. Then he continue to say that they only work until 16:00 and can not take anymore patients. So why book us for 16:20 and 16:30 but then you only work until "16:00"!!!!