dmc costing me money

I have accounts with dmc I called and emailed that im unemployed anymore as I was dismissed at work so they must up date their status to un employed and stop the debit order as im not getting any salary anymore, the lady that I got gave me an attitude and finally she said she will but every month they try to deduct even twice a month sometimes and this is costing me money as I owe more than R2000 on bank charges and whose going to pay for those charges as I did inform them of my employment status, im very disappointed in this company as they dont think for others they shouldn't even in business.