My Mercedes Benz 2002 c240 ignition key wont turn what could it be?

[SingleLatinMan29]

I had the car for over 5 years and never had this problem. Now when I try turning on the car the key wont turn it seems locked. I replaced the battery to the key and even disconnected the battery to no avail. Now I have a car stuck on parking mode and I cant even place it on neutral. It seems locked but the doors and lights work and I can close and open the doors with the remote key. What could it be?