bad service from the Capetonian restuarant

I booked a sunday lunch for my fathers 70th birthday. I wanted a nice quiet cordoned off section for my 42 mostly elderly guests. I was informed - when I went 2 weeks prior to my booking - that no reserved/special seating arrangements are allowed before hand as per their basic terms and conditions - - and that seats will be allocated on the day when you arrive. I arrived there at 11:30AM.. the first of the patrons of the restaurant to arrive. When I requested the back seating I was told that another party already booked that seats prior to the day (they even showed me the invoice that stated the reserved seating)... and was told there was nothing they could do, even when I reminded them of their own terms, they refused to help. They seated us in the centre, with lots of noise as that was where everyone in the restaurant lined up for the buffet. Im very disappointed in the Capetonian..I payed R7000 for a very unpleasant and embarrassing experience.