Unauthorised Debit order

Netstar keeps on debiting my account R1400 and the tracker that was installed on my car was ordered by the Oakhurst car insurance. The car was written off due to accident, so Oakhurst sent me an email advising that they settled 90% of the Netstar account on the 26th of March of 2015 and I paid the remaining 10% on 21st of April 2015. So I want Netstar to stop debit my account, want to confirm via e-mail that this will never occur and I also want them to repay my unpaid debit orders fee amounting to R120 since they debit peoples account without consent, because I don't remember giving them a consent to debit my account, the monthly premiums were paid by Oakhurst not by me.