Insurance claim, replacement device faulty

Hi , I am a frustrated customer. I experienced appalling service at the kwamashu bridgecity branch. My elderly grandmother was given a faulty decoder as an insurance claim replacement only to find its faulty when we got home the guy who gave her this device called her back when she got home. Told her to return the decoder if it doesn't work. I returned it and I spoke to a lady by the name of Zama , who upon trying to assist me got frustrated by a phone call that she was on . Then started lashing out on me. She told me the decoder was faulty I had to take it to Umhlanga for it to be sorted. I tried to tell her that Smanga told me to return it to the store , she caused a seen and called me deaf and dumb for not understanding that she told me the device is faulty and she cannot help me.