ARDR

Afternoon just encountered a problem I went out today, about 4 miles from home car opened up ok, started and drove fine. Parked and locked the car. Went away for half an hour. Returned to car and key fob was dead. Could not get into car. Remembered that you could pop the cover beside door handle to use metal key. Did that, got in but could not start the car as it is a button start /stop. is there a hidden key slot to use the key to start the car? Can’t find anything g in hand book. So if keyless entry and start button and your key fails. You can get in car but can’t start it? Is this right? Any knowledge out there…. No warnings given anywhere that battery was failing either!