"Waiting time at the clinic"

My mother had an appointment yesterday at the clinic for a minor op. She arrived at the appointed time, 1 pm as did everybody else who was to be seen that afternoon! Consequently she waited 5 hours to be seen. She is in her 90s & I think being made to wait so long was ludicrous. By the time she was finished the dept. had closed & the staff had gone home. Why did everyone have to be there at 1 pm? It wouldn't take a genius to have some better appointment system, surely. In all my years as an SRN I never saw the like. I would appreciate an explanation please.