Cell C not resolving the problem

In January, my Huawei handset went in to Cell C for a power-related problem. It was sent to Johannesburg, and after about two weeks they swopped it out for a new unit. After re-installing all my apps and data and starting to use the replacement handset, I discovered that one of the features wasn't working. After checking build numbers, etc., Huawei confirmed to me that I had been given the wrong version of the handset, and after keeping me waiting 6 weeks for an answer, they eventually referred me back to Cell C. Cell C have agreed to resolve this, but in order to do this, they want to send the handset back to Johannesburg for a system upgrade. I have requested a solution that minimizes disruption and inconvenience to myself - I have asked for the correct handset to be given to me to test before wiping my current handset, and once I'm happy with it, I'll migrate and return the old one. Cell C won't accommodate this request - they insist on inconveniencing me further. As this matter is not being resolved, I have asked for a reduction on my subscription, as the unit I am currently using lacks the features of the one specified in my contract, so I don't have what I'm paying for. I have been assured that this matter has been referred to the CEO and top management for a decision, but nothing is being done and they remain silent. I find this discourteous, immoral and disdainful.