bad attitude by Chicken licken Potchefstroom N12 manager

On Friday the 26th at just before 7pm, I bought a family full house 8piece from Chicken Licken Potchefstroom N12. I was given a receipt which was taken back upon receipt of the food. When I got home, there was only 6 pieces of chicken in the box when it was suppose to be 8. I immediately called their office to complain and spoke to a lady by the name of Esmeralda. She blatantly refused to assist me her reason being that I do not have a slip and I didn't know the order number. I told her that there's no way that I could have the slip because she knows that in their restaurant, they take back the slip when giving the order. She insisted that I give her the order number and I made it clear that there's no way that I could remember that order number and that I would have memorised it if I'd known that they'd give me an incomplete order. She then refused to assist me saying that I must provide a slip or give her the order number and she said that with a very bad attitude asking me what I expect her to do because I don't have a slip when she knows very well that all their customers leave their restaurant without a slip. She furthermore told me to go ahead and report her to head office because I'm being impossible. I've been a loyal customer for many years and I do not expect to be treated with such dishonesty and disrespect as this is not the first time I experience this from their restaurant. I've got a bank statement to prove the amount that I paid on that meal. I'd really appreciate your urgent intervention on this matter. Thank you