Seems like a huge coincidence it stopped working at the same time it was visiting the dealership. I suggest you take it back and complain that they broke your seat.
You have nothing to lose and will probably get the fault diagnosed free and maybe more...
Engine sensor , ignition control sensor ! Is the vehicle check engine light on ? Do you have a scan tool to check engine sensor data ? Do you have a DVOM - digital volt ohm meter ? any sensor that is powered by the PCM - engine computers five volt reference voltage circuit . 5 volt reference or crankshaft postion sensor . Doing testing is the way to find the problem .Check out videos on ignition system testing .
You will need the key to unlock the steering so that you can remove the ignition housing. This is done as an anti theft measure. The only other way is to get a locksmith to unlock it for you, or break it.
The easiest solution to try ...
Get some silicon-based spray lubricant at your auto supply or WalMart (dont use graphite) and spray it into the lock. Sometimes foreign substances can enter the lock and cause this, or someone else may have sprayed some other type of lubricant in there before and it gummed up. Spray it in there liberally to flush it out then work the key in and out a few times to make sure all the moving parts inside get coated and lubricated. Make sure you make provisions for overspray and dripping. If your problem goes away, there you go.
You can buy the replacement pigtail connector at the auto parts store the connector plugs on the back of the bulb inside the tube on the back side of the headlight box you remove the rubber dust cover and pull the old connector off the bulb plug in the connector on the pigtail and splice the wires to the old headlight wires all of this is done outside the headlight box there is no need to remove the headlight box.
The wire connector plugs on to the back of the bulb inside the round tube with the rubber cover on it the tabs on the back of the bulb are not inside the headlight box.
Pull the rubber dust cover back you will see the electrical wires going to the bulb you can pull the old connector off from there it is not inside the housing, the bulb is held in by a small spring clip at the back of the bulb socket.