Billing For A Sold Vehicle That's Been Transferred

I sold me vehicle in December and informed Tracker that the vehicle have been sold and the new owner would like to transfer the tracker contract. Track advised me to let the new owner send an email with his details and they will transfer the contract. The new owner contacted Tracker and got the vehicle transfer to his name. I was later shocked when got billed and also the new owner got billed. I contacted Tracker and they did refund the money and i told them i sold the vehicle.<br> <br> The next month i got billed again and spend a lot of time on the phone and the agent said i am supposed to keep paying until my contract expires, i tried to tell her but she didnt understand. The agent also told me they will call back. I never received an callback<br> <br> In March i called Tracker and they informed me they will pursue the issue and call me back. I never received an calls. So i gave up, then i started getting calls from Trackers automated system that the vehicle had entered a dangerous area. I told the agent i don't own that vehicle, i sold it and informed Tracker.<br> <br> I have been waiting, and i keep getting billed for an agents mistake. I need my money Tracker.