1999 Audi A6 Air Bag Lite stays on

This car has been damaged on passenger side of car.
Because of the damage, it had a water leak with water coming in somewhere around the fire wall on the front passenger side of car.

I attempting to find and repair this water leak, a body shop, pretty much stripped down the inside front passenger and drivers side.
After getting everything back together, they could not get the "Air Bag Warning Lite" go go off once the car ignition switch was turned on.

How do I get this lite to go off?