Car won't restart

North69

I have an 2007 G6 2.4 it's had the starter, alternator, and multiple batteries replaced recently. Problem is I'll go to the store while someone runs in the car (parked still running) will show power steering light, then security light. When you turn it off after the lights show, it won't start back up. The battery is drained everytime but it's a new battery, tests good, new battery bolts, the alternator is also new and tests good. My lights in the heating control come off and on when they want, air bag lights go off and on, seat belt lights always on. Anyone know what this could be or have this problem??