No assistance and rude behaviour

I phoned CellC earlier this year to enquire when I can get an upgrade. I was told to speak to Sipho and he was on leave so no-one else could assist me I just had to wait for him to get back from leave. So my phone decided to pack up today it's not switching on and not responding at all. I've had to borrow a phone from a friend. So I called in to speak to Sipho to find out if and when I can upgrade. Turns out I can upgrade and I wanted the Samsung S8 on the Top-Up package but it would cost me an additional R 150 per month, total contract value of R 879 per month, I'm currently paying R 729. He called me back to say that I'm over committed and that I should send through my payslip. So I did and I sent through my payslip and letters confirming I earn an additional R 8000 over and above my salary also sent through my bank statement so they can check if needed. He then called back to say my expenses amounted to over R 19000 per month. I told him maybe they are seeing my bond which is in both mine and my husband's name, but he pays the full amount, I don't. He then said I need to speak to Credit Vetting, which I did and explained the whole story again, and they said I had to speak to Sipho, I spoke to Sipho again and he refused to be of any further assistance said that I can only choose an open line. I then asked to speak to a manager and he refused! I phoned back and was told a supervisor Brian would call me back. So someone needs to sort this out, and fast! I mean all of this for R 150 per month. I've spent the past 5 years with CellC with no problem until now.