take the tape and all papers to a lawyer and file a case on dealer for fraud and also seek for compensation.. don't be late consult a lawyer before you get in trouble
Sounds like your dealer is guilty of fraud. Since you know he changed the paperwork you also have to wonder what he sent to the bank. You may be indebted to them for more than you know.
Most larger towns and cities usually have Legal Aid, which is lawyers who will help you for FREE or only a small amount. You do need a lawyer AND FAST. I'm just afraid a yellow pages lawyer would be more expensive than the car. You need to get on this fast. Go to your local Yellow Pages and look up "Lawyers Associations". Legal aid should be listed there. If not contact the local Bar Associatio ofr Lawyers.It will be in the same category.
Every state has different laws about returning a used car for a refund. In most cases all used cars are sold "as is" which means it's your tough luck if you drive it home and the transmission falls out. In your case your problem isn't about the CONDITION of the car, It's about the fraudulent paperwork.
If there is a branch bank in your area I would take all your paperwork and talk to the local manager.