1993 Ford F350 Power Window problem

I took my vehicle to a local body shop here in Las Vegas, NV.
My initial problem was that the power window motor
on the driver's side had worn gears and failed to
engage the gears on the regulator. This was told
to me by a SafeLite technician who installed a new
glass. (I had broken the old glass, trying to get it up)
He suggested I take it to a bodyshop since he did not
do that kind of work.

So I found a body shop, and I purchased a new motor, and regulator. They said they would install it.

When I came back to pick up the vehicle, I made the mistake of paying them first BEFORE checking to
see if the window was fixed.
I got in the truck and I tried lowering the window.
This time I got no sound from the motor(the old
motor would turn, it just didn't raise the window)
ALSO, the passenger side window also did not work.
(It was working perfectly before)
They agreed to "look at it" and get it working.
I came back and the windows still don't work.
Now they imply that it's my fault, that it's some
sort of short(no fuses are blown) and they're not
at fault. According to the Ford chassis electrical diagram, the power windows circuits are protected
by a auto-resetting circuit breaker.
Is there any way to test to see if the circuit breaker
still functions?
I personally think they probably pulled on a cable
too hard and one or more pins have come loose.
Any help and/or advice you can give would be most
appreciated.