you will have to call a tow truck or lock smith to open your door, you will need a title or something to prove its your car.
cant open the case to get to the dead batteries. How do I open the case
cant you said it your self DEAD BATTERY NO TURNING IT ON
With your key.
dead battery
Key
The most common cause for a Mercedes-Benz not to start is a dead battery. Try charging the battery to see the automobile will start.
You cant without destroying the battery. Manufacturer can.
With the key inserted into the lock.
you use the key in the door lock.
Dead cell in the battery or something is on pulling power from the battery. Have the battery tested at any auto parts store.
The answer is obvious. The battery is dead and will not turn the engine over.
crowbar works nicely