double booked seats

I am so unhappy with the treatment I received at ster kinekor Sandton. My sister and I bought tickets at the counter. When we went there, people had already occupied the seats and they had tickets for the exact same seats (movie: oh shucks). We went to the manager and he gave an excuse of they close the doors after 15 mins of trailers and it was house rules there was not much he could do as it would mean inconveniencing other people. He then took our tickets and told the projectionist to find us seats in another movie. I am disturbed and shocked at how loyal customers are treated especially when the manager himself stated that he changed the screening of the cinema from one venue to another this affecting bookings. He was very rude. I would not expect this from such a reputable company