I would simply go to the dealership  Extreme Ford in Crystal Lake IL
and make up a number of poster boards and walk around the sidewalk on
the outside of the lot.  Voicing your complaint. using words such as
thief, Ford credit uses thug tactics, Customer service null and void.
I would bet that your son is upset over losing the car.  he could
round up a number of friends from school, you could have a nice little
protest.  Get loud enough this local company will make things right.
I wouldn't say that my experience is the same as yours but when I was
driving to the closing on my first rental property I purchased, the it
was Feb. with 2 1/2 foot of snow on the ground and record low temps
for Iowa.  Then night I moved it was -30 windchill.  Back to topic.
Regardless when the seller had moved, he had snow plowed up through
the front yard removing the snow but also all of the sod.  Looked real
classy.  So I got into the closing got in his face and got loud told
him I was walking away from the deal.  His attorney recanted You can't
do that we have $500 in your escrow money.  So I kindly replied F*ck
off, I'll walk on general principal.  So back and for back and forth.
He attorney commented that I have never heard of such a complaint,
suck it up, just through down some grass seed.  I simply responded
that this was amature night, if he wants to come over this spring and
throw a little grass seed and ferry water bucket from his house feel
free.  Finally my attorney arose from her slumber and had a little
sidebar.  In the end, I walked away with $3000 cash at the end of the
meeting.  So the moral of my post is that when it comes to business
practices and things don't flow as the should, get loud, get in there
face enough that they think they are going to mess themselves.  Things
will go your way.