Unauthorized Debits After Cancellation

Telkom Insurance by Omart continues to debit my account after I've canceled their services. I have a receipt showing that my service was canceled however they continue to take money. I've been reversing the charge but it makes no difference. They threaten me to take action on me if I don't pay the service I've already canceled. I'm the one whose supposed to be taking action because I get charges from my bank with this stupid back and forth. Omart Insure - You cancel They don't.