Not willing to help a customer at all

I have been on contract with MTN for almost four years now, and have two phones on Contract with them. My Tablet S3 mini was sent in two months ago because it would not charge. I received it 5 weeks later from MTN saying that it was fixed. When I got home I and tried to charge it, it would not charge again. I went to lay a complaint and I was told that MTN send it to an independent company to repair the phone, and they took it in again. I have waited three weeks since then for this phone and it has still not been repaired. <br> Because of this delay and my need of the phone I asked if I could upgrade, the earliest they said I could upgrade would be 1 July 2015. I went in today (the 1 July 2015) and asked for my upgrade they said that it was only the 1 August 2015, although I was told by three different people that it was the 1 July 2015, one being yesterday 30 June 2015. I was advised to call the retentions department by phoning 808. I had called and waited for 37 minutes with no response but the call being killed. What's most frustrating is that if we are late on a payment our phones are switched off immediately, but their customer service is shocking.<br> I dont know what else to do...