This is a crazy story. Hence have a prior relationship with an attorney or two BEFORE you need one. As soon as the harassment started, he should have gotten his attorney involved.
They screwed up the contract, tough rocks, hire more qualified people next time. It appears to be a legal contract.
J, that resign the papers is one of the oldest tricks that dealerships use. And they typically will change the terms of the agreement in the process. While your issue appeared to be nothing more than a simple document error, I don't trust dealerships any further then I can throw them. I learned an important lesson years ago. Something kept bugging me about the deal that didn't make sense. It wasn't until I returned the lease car and six months later reviewing the paperwork that I finally found their scam... They double booked the %^&($@ leasing fee.