Say no to Netstar

Been a customer with Netstar for 3 years. Cancelled my subscription after selling my car, 4 months later and they still deduct money from my account. I stopped the debit order and they handed me over to a collection company. I have given them my ref number I got after my cancellation and still everyday some person calls me for arrears payment……?? I will not recommend Netstar as a tracking company to anyone! Beware