No feedback on account queries

For three weeks I have been waiting for feedback on my account. For the first time, I received a bill almost R1000 more than my normal billing. I contacted the call centre, who told me it was internet usage, however I own a tablet for this very reason. I was then told by someone else, it was downloads from the MTN menu- I have downloaded nothing from the MTN menu. An e-mail was sent requesting a URL report, last MOnday- I am still waiting., This after threatening to port my number, to cancel my contract- still utterly no response, This is absolutey shocking service, and all you keep getting are e-mails how MTN is trying to improve their customer service- what a joke.