pathetic service provider

I have been complaining about my overcharge on my upgrade but never ever got any positive reply only its escalated to billing and I have 18 queries opened & 8 closed so they open queries and & then it looks like they ignore it when u call customer care the different agent has a different story some can go to any extent to try to help you but the system does not allow certain information. and the system is always slow like the time I did upgrade mtn sa has become a joke with after sales service vv poor