Charged for 3 months for a new handset that hasn't been delivered

I placed an upgrade order on the MTN website on 30 July 2017. I was then called back the next day and went through the process of completing the order and upgrade. However, my phone has still not been delivered yet I'm being charged at the new upgraded contract amount. 2 weeks ago (31 Aug) I called the call centre and spoke to Dinelle who told me the handset was at the delivery centre but was incorrect (it was an iPhone 7 plus instead of the iPhone 7). She said she'd get her supervisor to contact me, but I haven't heard back from them since this discussion 2 weeks ago. Then yesterday I phoned again (12 Sept) and got passed around from person to person, of whom none could help and all just said I need to speak to Dinelle who has yet to call me back. I see I have now been billed again at the new rate...This is the worst service I have ever received. MTN - you now owe me money, sort it out and call me immediately. And don't send a generic message from Willem Loots.