Incorrect billing

Here we are again. With Vodacom and their contract lines, it's unfortunate that my mom can not express herself enough how this is stressing her and have this lines sorted. It's been months now almost years trying to resolve the same issue. She has been up and down to the useless walk in stores, countless phone calls and yet we get all. sorts of misleading information and a higher bill every month. Can someone competent in the sales department call us back urgently, this is causing my mom sleepless nights and frustrations. We can't be dealing with Vodacom every month over the same thing and have no resolution for so long.