Horrible customer service

I called Netstar last year to request that my tracking contract be cancelled as I am selling the vehicle. The consultant said I need to send the cancelation in writing. I then sent it in writing in April, sent another in October, sent another email in January and I have not received any response. Instead I got a call from Nimble saying my account has been handed over to them. How? I have sent email to no avail. Worst service I've ever experienced. If Netstar is not able to sort this out I will taking this to the Ombudsman.