Bad service

I cancelled a tracker on my old since U was selling it in 13 September 2021.I got email that I will get a response with 48 hours if not 24 hours. I waited. I then got a call when they realised that the debit order did not go through. I explained to the agent that I cancelled my account and she requested that I sent her the cancellation email, which I did. Since then I have never received any communication from them about outstanding amounts to my surprise I receive communication from Nudebt about outstanding amounts.None of their agents could explain to me what makes R463 bill.I requested an explanation and I get is that I need to speak to Nudebt. In April 2022 I received a statement from Netstar with uneplainable costs.If I owe them It should be the few days after cancelling.I received letter of demands from Nudebt.I found this to be not fair to consumers.