MIA Vumatel for booked installation

Vumatel made an appointment with me for the 20th of April @13:00 which was a Saturday. And their very clear on the fact to not miss this appointment or you will fall to the back of the queue if someone isn’t at the premises for the booked appointment. SO HOW DOES IT WORK WHEN VUMATEL DOESN’T SHOW UP FOR THE BOOKED APPOINTMENT THEY MADE WITH ME???? Do I still fall to the back of the queue due to their negligence? Poor service? I am so Disappointed!!