Bad Service

I have a mobile data account with Telkom which I have have signed for amount of R199 according to their contract, my first concern is the date of payment which I have signed for 25 of each month according to my salary day, Telkom have never debit on that day they always go to my account from the 1 of the new month, my second concern is the amount which they debit more than agreed amount, I have visited Telkom store in Centurion mall I was told that my service is unlimited which I did not apply for however the guy changed it to stable after that month still they continue debiting more. In a month of June I have decided not to pay account so that they can call me though I didn't receive call though my service was suspended, I have end up visiting another store at mall of Africa I was advice to call some number because my service showed that is a stable one on the system . I have called on Monday and phone was answered after a long holding the lady couldn't help I suggested that she call her supervisor and she promise, Have hold for a long time and when she came back to the phone she said supervisor is busy I must hold again, I then suggested that she must call me back since today am still waiting for that call, The service sucks and very inconvenience.