Demand payment even when service terminated

<p>I had a car that was fited with a netstar trcking unit and another car that i have sold that also had a netstart tracking unit. Now they demand me to pay for both cars even thou service have been terminated. They claim that i had a Verbal contract with them and i wa not aware of that.for the second cat they are chargong me twice as they claim that the tracking device fited is charged twice, i called the insurance company that fitted the tracking unit and they say thats not the case. why people are forced to pay even thou service are terminated ? isnt it thaty when you stop paying your tracking unit services gets terminated and you dont owe anyone anything after that?</p>