I used duplicate key to start 2008 jetta volks wagon it went into safe mode on odometer I am not able to start after that?

Duplicat as in you went to a hardware store and just had one cut or you went to a dealer and they cut and programed a new one? All post 2000 cars id say have it, its a chip in the key that is programed and works with another chip n the ignition to prevent theft and hot wiring, you probably triggered the imobilizer, if you got it done at the dealership then that's their problem.