Unhappy customer

Iam very much unhappy and disappointed with Matrix, it started when I had to renew my contract with them last year, one of their *********** installer arrived in my house to install a tracking device he told me that I was using an old device and I have to upgrade to the latest device fine I told him to put the new device, I could see after 30 minutes that the guy is not clear about his job, in such a way that after 3 hours of trying he left my car not starting and the device not working I had to call the Matrix head office to report the guy, I sent emails complaining about poor service, I kept on calling the guy to come and fix my car and he wasn't picking up my calls after promising me that he will send someone to come fix my car, after 5days of his empty promises I decided to fix it at my own expenses, I even ask the mechanic to remove the non - functioning device which was improperly installed I then called Matrix offices to cancel my contract with them, they said I am owing a cancellation fee of which I asked myself how can I owe people who came to my house and broke my car and never bothered to come and fix it even when I have reported, I still have the guys name and the emails I sent and those received from the head office when I was reporting, now Matrix people are threatening me with lawyers and putting my name on bad credit payers and I am so ****ed by that and so disappointed by the company and poor service I received my contact number is ***