Cavalair broken down not able to find a fix

Cavalier 2002, 100,136 KM, its engine died on highway first time last Oct and could not start. Then during the folowing month it was sitting at mechanical store for repair and never got repaired. Then my friend helped me with the car checked and got it running. But a week later it regularly died when starting, driving, or waiting for trafic lights. In cold/wet morning, it's hard to start. The whole winter it slept in my garage. Now its summer it even can not start with jumpers. It is my biggest headache since to be born. Why GM gave customers such garbage cars. Mississauga, ON, Canada.