Telkom is over billing and not assisting

i have a mixit contract which is over 24 months now, in my contract i have a mobile option which i am trying to cancel since April 2015, i call Telkom and logged a call after 2 hours waiting time, nothing happened, i went to Telkom Glen 3 times to cancel, still nothing happened, all that has been done is my line is no longer working but i am been charged for service. i called Telkom and put thru departments with no one who can assist.<br> <br> How do i resolve this - i am ready to cancel my entire line, adsl, line - everything