So rude..

I bought food at nandos liberty mall Midlands on Sunday and one of the burgers I bought was not given.the lady that gave my order told me everything was packed in the bag.i only saw when I got home that one of the burgers were not given.I then called the store 3 times and all 3 times they dropped the phone in my ear.so very rude of them.I then call the customer care line twice and it's been 3 days now and I have not heard from them yet.I please want something to be done about this or I will have to take this further.