Front bench seat adjuster not working

Lay a mirror flat on the carpet under the seat. By moving it around with a light under there, you should be able to see what's going on. Then you might be able to easily correct it without removing the seat.

Or, remove the nuts under the floor, lift the seat so the studs are out of the holes, and just tilt the entire seat backwards so the back is resting against the rear seat cushion. That might give you enough room to fix it without removing it from the car..