Telkom *****ulent *********** service

I have a cellphone contract with telkom for +-4 years. Never had a problem with billing now that they have made the mistake by over charging me and I reversed the money as it's mine plus it's money I need and paid them the amount they should've debited there are major issues...they keep on over charging me because of them over charging me???they debit when ever they want without authorization, they switched off my phone access (internet, calling etc) costing me money and making things difficult and all because of their mistake! I'm calling billing and i struggle with them to sort it out and says to me that there are no one higher or any number I can speak to,only them.thats bull ****. Can anyone help with a number like head office or ombudsman to get this sorted? Will be appreciated.