Cartrack reep off

My car hasn't been working for more than 6 months car track could have seen that since they say their device is being tested every month had to rebuild my engine the whole system was disabled battery removed they've already rated me as a bad payer but they never bothered calling to find out why is my device not functioning now they want me to pay them for all these months they should have frozen my account as soon as they realise my device is not functioning