Greetings

As stated in the title my Merc has a jammed igniotion/steering lock. It's locked in position 0(I can pull out the key) therefore I can't remove the tumbler. I have tried cleaning the inside of the tumbler using WD40 wich did not work. Neither did applying clear nailpolish to the grooves in the key. I have also tried both my keys. So I do not think it's wear on the tumbler/keys. Does anyone have an idea of what the problem might be? And if it's something I could repair my self without too much hassle?(The car is not in the garage and it's snow outside.)

Cheers WOTR.