Debit order stop instruction charged- service not delivered.

I had an account with no finance cars, whose services have been nothing but a nightmare. I had an accident with their car and they never attended to it till I skipped payment due to a technical error by the bank, which then forced them to send recovery department to collect the car on 4 April 2018 based on non payment of account. I told my account manager that I was unhappy with their service and don't want anything to do with their car. They debited full amount in April and I went to standard bank to request a stop on the debit order, which they loaded and gave me a print out to show me it was done. In May I the debit order went through, when I asked at the branch for it to be reversed they told me it can't be done and the debit order stop is not guaranteed, yet the bank charged me for the stop instruction. Even in June, July, and now in August I've accumulated charges for returned /unpaid debit orders. I want my money back and all their charges to be reversed.