Negligence that could have killed me

I bought a groupon and booked my car for a service. Wednesday the 4th of March i took in my car in the morning and i wrote on the one pager that was given to me to sign that no additional work must be done without consent. During the day i received a phone call detailing some faults and some bargaining ensued but i said no. <br> <br> I collected my car just after 4pm and my car's battery was dead for some odd reason. After they charged it, i started driving home. The car began making a lot of noise so i decided to turn around and go back to the workshop.<br> <br> I inquired about noise and the manager dismissed me telling me all they did was a service. I refused to leave and they ask a guy to check my car. He looked at the car and suddenly walked to the wheels and started tightening the wheels