If key wont turn: depress brake pedal while wiggling steering wheel back and forth, and trying to turn the key. I have this in my notes, but I think I read it in the manual at one time. This works for me and my 2009 Sonata, as well as our 2001 Hyundai Accent.
Hyundai as a car manufacturer put a lot of free technical information and workshop manuals on line for Hyundai owners. Check out www.hmaservice.com lots of great information.Isn't your car still under warranty?