Biiling Issue unresolved after 3 Months

This is totally unacceptable that a billing issue can drag on for more than three months. When my contract was upgraded in November last year, I specifically requested that the data be capped to 2gig on a monthly basis. It all went well until May this year when I was billed almost double. I was told by their East Gate Branch that this was a systems error. I have logged several queries and was promised that this would be resolved within 7 working days. I had to make enquiries regularly as nobody contacted me with any feedback. I have subsequently logged another 3 or 4 calls at the East Rand Mall Branch with the same old promises. The query was even escalated the Regional Manager. I'm still waiting for feedback whilst the services of my contract is getting suspended every month. They expect me to pay R 5 153.42 for data which I have not used. When it comes to resolve queries, MTN is very *********** and unprofessional. I demand action from them to resolve this matter speedily.