Shocking service. Deduct money but no idea why

I paid up my loan in September, asked for the settlement letter which I received. Now for 2 months money is being deducted off my bank account. Been trying for 2 months to find out what that money is for that's been deducted. No one helps, customer service says its insurance, insurance says policy is canceled and it is customer service who needs to find the reason why the money is being deducted. Cannot speak to someone who can help me, spoke to 6 people in the past hour and just get transferred back and forth. R500 is allot of money out of my pocket. Why must I battle to find out why you are deducting money when my loan has been settled. Why must I phone the insurance company when my loan is paid up.