Incorrect billing, no responses and awful service

I was moved to MTN from Nashua Mobile. I upgraded my phone at Benmore Center to an IPhone in Fenruary. I requested them to cancel my insurance and blackberry services. I asked if, when moving to the new package, would there best increase in my bill. They assured me there would not be. When reviewing my bill in March these items were still included. In addition, my phone was disconnected as I had, unbeknownst to me, a bill limit. I called the call center 7 times overview a period of three months. Each call had an average hold time of 30 minutes with this mornings at 43 minutes until I hung up. I tried another tack and emailed the help desk. The automated response said we will respond within five working days. No one responded. I went to the MTN franchise in Sandton City. They told me they could n help as they were a franchise. I ask the MTN branch of they could connect me with the credit or insurance department and when they called the response was that I needed to use the helpline. Four months later I have had no response and I am still being billed for insurance and blackberry services and am unable to increase my bill limit to R2500.