Double debit order

I signed with cartrack last year June, September same my car was written off, I phoned to cancel but they told me I have to pay penalty fee of 2.6, of which I ddnt have...they continued debiting my monthly contribution until September this year which marks a year paying for services that I'm not in use...I phone them and made a payment arrangement of 3 months which is Oct - Dec...Then 1st month they debited my acc twice the amount of (R89 and R1035)and in Nov they debited my account twice again on the 24th (R974) and on the 26th(R935).When I call them they tell me that my account is on arrears of which is the payment scheduled for Dec...I couldn't get to work today because they took my petrol money my job is now on the line.