Unauthorised debit orders

Firstly I would like to acknowledge that I had a contract with Telkom some 3/4 years back, I have never had any arrangement for Telkom to DEBICHECK my bank account, over and above that, this is based on the information I received from Khutso(your agent) that my balance was about R3000 but Telkom deducted more than R4800, when I called to query this, Khutso dropped the line after making me hold for 27 minutes. Can someone please assist me, if I am not able to resolve this with Telkom, who else can I speak to+