Bad service and incorrect billing

So after changing my insurance company, I had to take over my tracker and pay for it myself. With this, I was told by Netstar that I was due for an upgrade, which after some consideration I though I should just get it done. Seems this was the biggest mistake ever. After the upgrade, the unit hasn't worked for most of March month, then panic button only started working recently and not only have I paid for the last 3 months out of my own pocket, they have also decided to charge me a pro rata rate! In speaking to customer services, I was told that this was charged incorrectly as it was an upgrade and not a new installation and they would rectify it but low and behold, they have still charged me. Beginning to feel like they don't have the clients best interest and are just out to make money. While the unit wasnt working I also asked what happens if my car gets ****** and all they good say was is sorry for the inconvenience. Can't believe how badly they have changed over the years