MTN Overcharge and no intention to rectify

My cellphone is currently not working, so I am not using it at the moment, my contract per month is R299, which includes R200 airtime. When I receive my bill, it is more than a R1000 for the month and I haven't even used my phone because it is not working, the sim is still in and I have not made any calls. Upon raising this issue on the 5 Feb 2015 to MTN Call Centre on 808, they said i must wait for the bill to close on the 14th and request an itemised billing. On the 15th i requested an itemised billing, which did not come, on the 23 Feb 2015, I requested an itemised billing again, upon receiving it, I can see numerous calls made and charged to my number, I have a bill limit of R500 on my account as well, yet my phone did not get softlocked and R500. Now I call MTN over and over, the manager is always busy and I have to pay this bill whether i can afford it or not, I find this very unfair from a company that I have been dealing with for 8 years, there is no consideration, no urgency or honesty to assist a client from wrongful billing.<br> I am utterly disgusted with the level of assistance from the MTN staff to help me with my account and leave me to pay such a huge bill, MTN USELESS