Very bad service

Hi I have been trying to get assistance from telkom for mistakes they made, but no one is helping. I have phoned the call centre 3 times, I went on the online chat, I went on Facebook chat, but no one helps, nothing has been rectified and no one phones back. I have to pay for charges that I did not consent to. How and where do I go to take legal action? Anyone who can help?!?!