Nedstar failure in customer service

I took a policy with dotsure insurance and it came with the nedstar tracker, dotsure triple debited me and I canceled the policy and left the dotsure account... In April my car got written off, I called nedstar but their phones are never answered then I decided to send an email to inform them and it wasn't responded to. 2months ago they started contacting me telling me my account is in errears and I told them the car was written off and I had tried to inform them, the consultant named Norman told me that nedstar only responds to important emails, meaning mine wasn't, I told them I don't know where the car Is and I will not pay the amount in errears cause I had tried modes of communication to tell them.