Hyundai — battery problem

I have going to the service center i.e eros hyundai Nagpur for the servicing of my hyundai eon but next day when I go to pickup my car my car battery is totally discharged and when I give my car too the servicing representative my car battery is full charge and when I complaining to the staff their reaction is very bad bad service too shame on u all people of eros hyundai Nagpur. . . .