Why can a malfunctioning phone not be reembursed?!

My insurance claim phone was malfunctioning from the first week of receipt. I returned it within 5 days for money back or new but management claimed that this is not for them to decide. Johannesburg head office is in charge!! Why is that?? I have now sent the phone back for a 3rd time, still demanding a \repair or assessment"is not in order and all I get is management saying they cant help and an sms saying the phone is now at a higher level of repair!! What nonsense!! No one in Vodacom is prepared to follow their empty televised promises of customer service is number one on their list! I have on every occasion phoned customer care lines in Jhb only to constantly hear that the person in charge in actually not the one in charge! A higher level of management will call back. Needless to say they never do! The time line without my so called new phone is now calculating one whole month and still I cannot get anyone prepared to take responsibility. Not even Sony themselves are taking the blame. The more they work on the phone the worst it gets! It's a joke! Garden Route Mall Vodacom and Johannesburg client services are NOT doing their jobs! I need help urgently!!!! """