No change on my account over billed

I complained several times regarding mtn over charging my contract no one came to me they just respond here no one has ever contacted me directly to hear me out,i called the manager of Eastgate branch I was told he was busy I had to look for him for two days I found him eventually he investigated the matter and found that there was insurance that was added there that made the amount to go up to R309,he told me the insurance will removed but until now they still bill me R309 and they are going to suspend my account again. I'm really irritated by the way they do their business they just don't care, their customer service is so unacceptable as a customer you always have to run to them to fix the mistakes that were created by them.