Terrible customer service

On the 19th of August I bought a Nokia C1 cell phone from them. First off al the box was not sealed. I asked them why and they told me that they are giving me the demo phone in the display box. They assured me that the phone has no problems and that if there was any problems they would exchange or refund me the value of the phone. After taking the phone home I started using it 5 days later and it had a huge problem throwing out white screens in the middle of a google search. I can took it back on the 24th and the Manager Charles refused to refund me any money. Said that I must take a more expensive phone or the same value phone.. the closest phone to the original phone I took back was R100 cheaper a Mobicell R7 phone and he REFUNDED the R100 after tellinge that it's not allowed by the Ackerman's group. Now over the weekend I've noticed that this phones battery is faulty and that it gets very hot at the back while browsing the internet ? At this stage I'm fed up with Ackerman's in North Park mall cus I know what the Manager is goin to tell me when I take this one back asswell " no sir we don't do refunds" I want my money back please after two faulty phones I cant go through this time and money wasting experience again. Really terrible after customer service