I'm not happy with the service!!!! I just got a 20...

I'm not happy with the service!!!! I just got a 2014 Chevy Malibu and it has stopped on me twice. This month will make it three months since I got the car. I took the car back once they said everything was fixed. A week later it did the same thing. I have missed two days of work because of this problem. They gave me a car to drive while my car is being fixed. But, the car had zero gas in it!!! They have had my car for three days. I called the service manager twice yesterday he called back. He told me it was the core to my battery. I called him again today three times!!! No one has returned my calls. I'm starting to believe maybe they don't know what's wrong with my car. So now I have to pay for a car that doesn't run like I thought. I would've kept my other car if I known this was going to happen!!! I'm so upset and frustrated about the service I have received. It's only been three months and I'm already having issues.