Bad service

I am not happy at all with cartrack. I told them I am no longer using standard bank and using TymeBank and they said they can't debit TymeBank. I asked them to please stop debiting standard bank as I'm no longer using the bank and the consultant agreed. I told them I will make eft payment and they agreed but now they keep 9n debiting my standard bank account and the debit order keep on bouncing back and the bank charges me R150 for a returned debit order. I can't keep 9n paying for cartrack and the debit orders that keep on bouncing. I regret taking a contract with cartrack company.