Customer service

I went to KFC near McDonald's by small street to buy a meal, and I was assisted by a lady called Tiyani. My meal had two gravy', 8 pieces of meat, chips.. When I checked if everything is there they gave me mash potatoes without gravy, when I asked her she gave me an attitude and became rude towards me, she didn't tell me that there was no gravy and I paid full amount.. I'M SERIOUSLY NOT HAPPY WITH THE SERVICE I GOT THERE AT ALL