Review Unfair Reservation policy

I bought metrodeal vouchers for yakimix sm north. When i made my dinner reservation, i was informed that i need to be in the resto between 5-5:30 pm only. I asked them why they are imposing on me the time when i would be at the resto. I told them what if i wanted to have dinner at 7pm. They said they will cancel my reservation after 5:30 pm. I told them that the purpose exactly of a reservation is to get a table at ur preferred time for a certain number of people who will dine with u. Yakimix can only impose the time period for dinner time (say, 5pm to 9pm) and it is up to the customer what time she will come within that period. U cannot say u will cancel the reservation after 5:30pm. That defeats the nature and purpose of a reservation. I asked to talk to a manager but they became evasive. I asked for the contact details of the head office and they refused to give me. Yakimix, that is lousy customer service.