Bad service

I'm driving a chevrolet cruise it gave me a problem it used to show a battery sign and for 2 days. I called the chevrolet service/repairs department and told them about the problem, they booked the car in for assessment. I sent the car later the same day, they called me and the tell me they can't find what's the problem with the car but will the following day. I received their call the next day telling that they must replace a computer box. They did but the problem is not fixed so they need to order another part but they didn't give me a courtesy car I spent a week without a car. They call me today that they must order another part in Cape Town and it will take 3 days for them to receive it, I asked them to give a courtesy car they sad they don't have any now. It's another 3 day without a car which I'm not sure if they manage to find out what really a problem with the car because they had that car for a week but they not really sure what a problem is.