Unapproved /********** debiting of my account

I cancelled my contract with telkom in July. Every month since then, more than once a month they have been debiting my account. I went in store and they too couldn't tell me why and said the would escalate it and I would get a call. It's been over a week now, no call and 3 more deductions. Yes 3 deductions and reversals all in this month. I have tried calling the call center to no avail. Can someone please assist me.