Dealer oil change. Now no oil

Yesterday I took my jeep in to have oil changed. Driving home I saw a little white smoke at stop however figured it was excess oil on engine burning off after oil change, then my oil pressure light came on. Once home I noticed oil drops on ground and puddle of oil forming under car. Checked dip stick 45 minutes later and car has no oil.

My question is what now what. I called dealer and they sent a tow truck. Driver arrived and advised that a mechanic from dealer needs to come out and advise before moving the car. He then left.

Also, what checks and balances should u ask about. It's an expensive lease car. How do I ask for a guarantee that no damage has occurred. I'm sure somebody just forgot to tighten something but now I'm very worried.