Why not to use Cartrack

Was on a prepaid service, cancelled the subscription after about 7months. I was the phoned and informed that I was in arrears, how could a PREPAID service be in arrears? They kept harassing me with phone calls for the so called "arrears" amount. out of shear frustration i just paid the so called arrears just to be rid of the harassment. this means they forced me to pay for a service witch am no longer using, further more I paid for the tracking device up front. So it makes the device my property, witch was not returned to me, whose in the wrong now? I want a refund on the equipment that I paid for upfront, My best guess its that's not gonna happen. so be forewarned when doing business with Cartrack, you will regret it n the long run. I am now with Netstar and very happy with their service so far,