Working with Chartis Life to deduct money from my account

I cancelled my policy with Chartis Life in 2013 , for some reason they started deducting money from my account for no reason , which ABSA bank allowed , I went into the branch to be informed that if there is insufficient funds in my account the bank charges amounts of up to R150 , they are charging me for debit orders of R27 , the policy has been cancelled for year and I do not know how money can be deducted from my account if I did not give permission.