Account Problems - Refund Due

I am desperate for help. For 4 months I have charged for a device that I don't have - was not part of my contract. I have more than a dozen call centre reference numbers and each time there is a new excuse for the problem not being sorted out - I have alot of money due back to me from MTN - all I am trying to do is find a person who actually gives a damn to help me sort this out.