2012 hyundai elantra will not start or crank

The car wouldn't crank or start when I got to the gas station.  After multiple tries with
putting the car shifter in park to neutral and switching the gears it finally started.  I
called the dealership and took it down to get looked at.  As I was driving it down to the
dealership as I was approaching the traffic light I realized the car wasn't running
anymore and by this point I had limited brake assistance and also lost all power
steering and had to use the e-brake to help with stopping the vehicle to prevent the
accident that was about to happen.  This was a great thing that I was driving and not
my wife as she would've froze and might not have been able to think how to get the
car to stop in which this could have been a accident with bodily injury or even
possible death of the person driving the car or the innocent person that was collected
up in the accident but no one would know as it didn't happen, thank god for this.  I had
the car towed the rest of the way to the dealership and they looked at it and the car
started for them and they tested the Battery, alternator, and starter and all tested
good so they gave the car back to me stating it was the AC invert-or that was plugged
in to the cigarette lighter.  I told them that I plugged the invert-or in after the car died
to charge my phone but they still insisted that I was lying i guess.  I drove the car off
the lot and a few days later the same thing happened again but I was going 35 mph
and was able to stop the car with no incident as I was afraid to drive the car normal
speed and knew it would happen again as the dealer ship had not found anything
faulty.  Now it sits in the driveway and is completely dead and will not start.  The
dealership Major Hyundai of Stroudsburg, PA 18360 will not allow me to bring my car
back to them and Hyundai will only tow it to the closest dealership which happens to
be them.