Sonata Key will not turn

The ignition key will not turn when inserted into the switch. I have tried to make sure the steering wheel was free from lock position and transmission in park position but still the key will not turn. It reminds me of a old car when the teeth would wear down over time and not engage the tumblers inside the ignition switch port. At this point, the key will not turn and therefore I cannot even put the car in neutral in order to tow or move. Any suggestions as to why the key all the sudden stopped working, will be appreciated. Thanks for your help