Ignition Switch problems of the 2004 Mercedes Benz E320

The ignition switch failed on my 2004 mercedes E320 wagon which only had 85k miles. If it had failed and just would not work, that would not have been such an issue, however, when it failed it left the engine on requiring me to disconnect the battery to get the car to shut down. Steps to reproduce: 1) put electronic key in car 2) turn key to fully on and start car 3) turn key to off position and remove key from ignition entirely note car is still on and will not shut off even after an hour.