Buy one get one free ****

On Sunday I ordered a but one get one free and only received one (not the second free item) the price was R269 for 11 pieces of sushi. I phoned the restaurant and the told me this is the how Uber deceive their clients because you technically pay double and the have received many complaints. I feel this is not only against the consumer protection act (as the wording is incorrect... it should be buy two for 50% off and NOT buy one get one free) it is also daylight *******. Why would I pay this amount for the quantity. I need them to credit me R134.50 or actually the full amount since I only received half of my order.