Unacceptable devices

I am totally disappointed and dissatisfied with Cel C at the Kollenade branch. 5 times a device has been returned with the same problem. Calls are being dropped, battery overheat, spam subscriptions (loaded by itself) . The people can't hear you over the phone. It goes in air plain mode by itself. Every time it is just send back. And then I am being told to pay in money for another device, it is not acceptable. I want my cash back and no defaulting devices. Give me my money back or I am going to Beeld I paid R900 for absolute *******.