Clinic appointment system not working...

Why do you have an appointment system because when we get to the clinic we are not well prepared for? I booked for a vaccination appointment for 12:30 today at Clicks east Rand Mall. When I get there they have run out of the vaccination. when I ask the Nurse (Sylvia Coetzer) why this was not prepared for, she told me she was busy and she did not have time to check her emails to see if there was such an appointment. So I basically wasted my time.