My vehicle has being ****** and recovered by Altech Netstar but they still charging me every month for damage unit.

My vehicle got ****** round about the 25th January 2017 and the unit in my vehicle is damage but Netstar is still billing me every month and to top it all they even increased the instalment. I being struggling since than to get this matter sorted out. I spoke to various people in their customer service and even tested my unit which they confirmed that it is not work or there is no signal. I also advise the people in customer service that the vehicle is badly damage in side and the guys that ****** the vehicle damaged the unit but they unprofessional staff don't even know head to tail what is going on. Than they put me through to retention not sure who I spoke to but where going to refer the matter to Shene as a team leader or supervisor she just don't bother to get back or she just don't value her customers. The auto body is trying to repair my vehicle and I would like fit a new Netstar without charge or please give my refund and I will go elsewhere if you cant retain me as a customer.