Refund owed after cancellation 6 months and waiting!

Cancelled our service Feb 2017 (landline & internet) yet monies are still debited off our account to date Aug 2017. Monies owed approximately R6k which is not earning interest in our bank account but rather in Telkom's account - this is theft! I have spoken to at least 5 people within Telkom's account department; sent emails and still no answers or apologies. I am disgusted with their lack of accountability/responsibility to their customers who are paying their salaries ! I will never ever use Telkom for anything again !