Cheated

I spend about R200 per week at Kauai in Rondebosch. I had recently downloaded the app and was entitled to a free smoothie to the value of R39. I thought I had read this prior to redeeming my voucher and I asked the cashier for a large berry dairy smoothie. He tells me I can only have a small and even checks with the manager called Zaid. Zaid confirms with utmost conviction that I can't have a large and cannot even pay in the difference if I want to upgrade. I then agree to take the small and immediately after I read the t's & c's again and show the staff that they had made a mistake. I'm then told that there's nothing that could be done about it now and not even an apology. That's exactly how to lose a loyal customer for life! Cheers Kauai Rondebosch!