Poor service

I went to the John Dory's Cornubia restaurant for their half price Sushi special. I ordered their Sushi platter, only to be told that it was not on special as per their terms and conditions. I would like to know where do I find their full terms and conditions, indicating that specific Sushi platters are excluded in their half price special. Further to this, the Manager, Precious, at the store changed our Waiter, I'm not sure why. Such poor customer service. The manager was very rude. Never expected this from such a well renowned restaurant as John Dory's.