Not sure if this is the right place to post this but has anyone had problems with their security light popping up and the car stalling after about 2 seconds of being started..

I thought the keys just needed to be programmed again or something, but the dealership is telling me it's the entire anti theft system including the lock solenoid.. Has anyone replaced all of this before? I feel like i am getting screwed out of 800 bucks.. Any input would be very helpful. Thanks