False advertising

I visited Steers Wonderboom junction and was not pleased with what transpired regarding my order. I wanted to buy quarter chicken and chips and I was told they only serve breast portion and no longer offers legs because of their suppliers. That didn't sit well with me as a customer because on TV they advertised a leg and even in the store adverts indicate leg but we are served breast. So can Steers explain the CPA rights where customers have freedom of choice as well as false advertising. You cannot be advertising something but offer customers something different? I'm so disappointed and want that to be rectified.