First disconnect all power to your oven.
Second check to make sure you have power off.
Third maybe shut off power to the whole house.

Then, carefully push aside insulation from around the cut out for the bracket which holds the wires and element.

Then, since the wires are going to be heavy gauge, it is unlikely they bent and fell down very low. You can probably use a short coat hanger wire to fish for the wire/bracket and lift it back up to the cut out.

More than likely, it didn't fall, it shifted left or right and is just a little out of sight.

Otherwise, no big deal, you can pull the oven out of the wall. On some models the upper oven can be seperated from lower oven and removed on its own. Look at the installer manual and it will give you some insight.

How to remove kenmore wall oven to find lost element wire