CONTRACT TERMINATED BUT I AM STILL BEING BILLED

Hello Peter, i have cancelled or terminated my contract with telkom on the 19Mar2015 in midrand. i had no longer required their service due to bad service they have given me. Today its the 26May2015 and they still deducting. Went back to midrand branch again and they said they have referred my compliant to account centre. Nothing was done and called call centre once again and same story that we will refer your complain to their accounts departments. this is frustrating for paying something you do not even use even though my line was disconnected. Why am i still paying them for? are they taking advantage that no one will do anything to them or undermine their clients? Please help me sort out this issue as i have 3 reference numbers which i find very useless right now. Thabo