Try and turn the steering wheel at the same time to take off pressure. If it still wont turn call a locksmith we are usually cheaper than the dealership or if you a mechanically inclined let me know and I will try and tell you how to remove it but it is a lot of work dash will have to come out. Probably what happened is the retainer cover that holds in all the wafers has popped loose very common with gm new ignitions they were better off with the old system hope this helps you