Netstar *****ing money for 6 years without proving service

I had a Netstar tracking device installed a couple of years ago and have been paying a monthly fee to Netstar.

I had been postponing to test the tracking device for many years until a couple of weeks ago.

I first called the Netstar call centre in September but was told that the call centre agents were busy and would call me back, this never happened.

I then called Neststar again on 25 October 2021 and requested that they test my tracking unit. The agent told me that he could not test the unit and told me that the unit needed to be updated. When I pressed him further he told me that the contract for the unit had expired 6 years ago and therefore Netstar are not able to trace the car. This made me very angry because I had been paying Netstar for 6 years for a unit that has not been working. For me this constituted theft because Netstar should have called me to tell me that the device is not working and needed to be updated.

I then requested that the debit order be cancelled immediately, however I was told that I needed to give a 30 day notice which I refused because I would be paying Netstar not to deliver a service. The agent insisted on the 30 day notice, of which I requested to speak to a manager. I was told managers were not available because they were in meetings, I was told that a manager will call me. This never happened. The reference call for this call is CAS-***-P4R5.

I called Netstar again on 28 October 2021, I told the agent my story and requested to speak to a manager so that the debit is cancelled immediately. The agent told me that there was no need because he will cancel the debit order without a need for a 30 day notice. The reference number for this call is CAS-***-C0B5.

To my surprise on 02 November 2021 my account was debited, I then reversed the debit as a matter of principle. Since then Netstar have been hounding me with their debt collector and sending me messages to pay if I want to avoid being blacklisted. I take this as a form of bullying South African consumers with threats of blacklisting so that we the comply and they get away with *****ing our money.

I now get daily calls from this debt collector and told that I am in breach of a contract. How can I be in breach of contract when Netstar is not able to provide the service it wants me to pay for? Is Netstar not the one in breach of contract for 6 years for taking my money without providing any service?