Bad customer service

Kfc musgrave , my friend and i went to their musgravr centre branch , we ordered two wrapsta boxes which come with soft drinks but they gave us water instead , we tried sending kfc numerous messages only for their customer service to phone and repeat the same thing we've clearly stated on our communication with them , all they gave us was a ref number i don't know what's there to investigate because we even took pictures of the water they gave us.