Incorrect billing and shocking service

Logged a call In October due to incorrect billing, to date I’ve spoken to 4 consultants and they requested documents so they could log a case. To date no one has helped me. I spoke to a Ntsako, Pretty, Masamgo, went to Mall of the South. Even went to their store and they advised they don’t deal with customer complaints. Now they blocked my line. Customer service is non existent and you can hear when you speak to their call center stuff that there’s no interest or passion!