Ruined my car's electrics

So I recently bought insurance with Outsurance and they are great and they referred me to Matrix to have my vehicle fitted with a tracker. I had it fitted at Sound Dynamics whose service was terrible. Firstly they called me and said they would send a technician and they did not, I had to call them to get it installed. Then within 20minutes of leaving their shop my electricals started acting up and my car would not start. I called them and immediately they said it was not their fault.I did nit have a problem until they set up alarm.I was upset and after 30 minutes finally managed to start my car. Now it stopped again a few days later and it is the electricals. A funny sound comes out from where they fitted the alarm and when I asked them to take a look they said they would get back to me which they did not . I eventually called them again, gave them my address again and still nothing. I am taking a bus to work with my car parked at home because they ruined it and refuse to take responsibility. I am very upset by their service. I called customer care to see how they can help and I was told to go back to the shop. I work all day and have no car since it isn't working to do that.