Disgusting service from Netstar

On the 31/01/19 I had Netstar replace my old unit for a new unit. Ever since this has been done I have had more problems than I need with this company. Shortly after the fitment my speedometer stopped working. My cubbyhole on the left hand side fell out. My car radio battles with reception. Then I started having problems with starting my car. Had to have my car jumpstarted many many times. I called to complain about it but kept making out that it was my car not the device. After many many calls it turned out the old device was still in my car and was still connected- this was what had been ****ing my battery. After a few screaming matches they sent someone who disconnected the old 1 but couldn’t remove it as where it had been placed where they couldn’t get it out. After this it all seemed ok however on checking on the app I could not see my car. I called again and have been told now that this device is faulty as it can’t be picked up ????. So now I wait for someone to fix it. I had asked to speak to a manager - they were busy so they said they will send a mail asking them to call me. I wont hold my breath. Not once after my many battles have they called to see if I’m ok and if all was sorted out. They said that I would have to pay in should I want to cancel the contract and pay a further amount to remove the device. I have been a customer with Netstar for 18 years and by now I should be treated as a gold star customer not like a piece of ****.