Over billing

I hope someone can help me as attempts through the other channels of telkom seems to be fruitless.<br> <br> I have signed up for a telkom simple contract in June 2015 for R499 pm. Telkom has billed me in excess of R800 per month. I have tried to dispute this, and they have reduced the amount to R622 and not given me any credit for the excess they have billed me before. This package is all inclusive line rental, data bundle, installation, modem, weekend and evening T-T calls , and yet they bill me individually for every service and equates to more than R499.<br> <br> Please, can someone help me with this? Telkom can not simply charge me more than we agreed upon.