When this happened to mine, it was due to a small bit of aluminum dislodging inside the steering lock, which consequently jammed the steering lock. I dis-assembled it and removed the bit of aluminum, which was apparently just a small pin used to hold the internal assembly in place prior to mating with the lock cylinder at the factory. This little broken pin got stuck in a groove inside the steering lock, preventing it from rotating properly. Once cleared of this obstruction, the steering lock works perfectly, and is a simple & virtually bullet-proof device.
PM me with your email address, and I'll TRY to send you some pics of the inner workings of the steering lock, etc. (My computer skills with sending pics are not good; sorry.)
While you have it apart, you may as well replace the ignition cylinder, which comes from Patrick at BMA for ~$58, already set to your key, if you provide him with proper info from your car.