Worst service ever!!!!

I had a car tracker contract with netstar which I wanted to cancell before the three- year period comes to an end and they told me I need to pay R1000 upfront as the cancellation fee. I then opted for continuing with the contract and told them that should the three- year period comes to an end they should cancel my contract because I no longer need their services and I was informed that they will cancel it. Last year December was the last month of my contract with them and I reminded them through email that they should not renew the contract and cancel it immediately. I received an automated response indicating that they have received my request and have forwarded the email to the relevant person to assist. On the 28 January I see a debit order of R239 by netstar!!! My contract with them was for R150 but they have been debiting R239 for the past 12 months. I need this contract cancelled ASAP.