Poor Service from MTN: upgrade offered by the company, but phone not delivered (2 months outstanding)

I was contacted by a MTN sales consultant in the last week of November for an upgrade to my mobile phone. The upgrade was conducted by telephone and at the end of the call, the sales agent indicated that I would need to be available the following week to receive the phone, as I had to personally sign for the receipt thereof. I advised the agent that I was in Cape Town and would not be returning until the second week of December, and thus could not take possession of the phone. Three weeks ago, I went into the MTN service centre in Morningside to find out was happening with my phone. The agent there indicated that the account was still open, and that she could not assist me by cancelling the contract or to provide me with a phone, as the account needed to be completed by the sales agent. A week later, I received a telephone call from someone who I believed to be a supervisor of MTN. This person asked if I was happy with my phone to which I indicated I was not, as the phone had still not been delivered to me. She indicated that she would follow up on the matter. Last week, I went into MTN at the Rosebank Mall, only to discover that yet again, nothing has been done to complete the upgrade and yet again, there is nothing anyone can do, except to email the sales agent again, and to escalate the situation to the technical team. It seems that there is a new system that does not have the facility to stop or cancel contracts. Furthermore, there is an out-bound call centre which can be contacted by email only. I was was told that I should receive some response and/or the new phone that day. Well., it is now Monday. I have heard nothing from anyone at MTN. In the meantime, I have either lost or had my old phone ****** from my bag, while out shopping last Wednesday. I am a psychologist in practice and need my phone. I have been a loyal customer of MTN since the first mobile phones were on the market. Can someone please help me??????