You have a range of choices, none of which are really attractive.
Return to the dealership and confront the management. You need to be very confident and have the ability to negotiate against skilled salesmen and do it under stress. You don’t have a chance. You know it and the dealer knows it. STAY AWAY. Not recommended.
File a complaint with the Better Business Bureau or the Consumer Affairs Office in your county. They have no ability to force the dealership to do anything. I’ts all voluntary. Just a further waste of your valuable time.
Hire an attorney and file a lawsuit. This is usually your best option EXCEPT it is hard to find a lawyer that sues car dealerships and even harder to find an attorney with significant experience who will not charge an arm and a leg. If you find the right attorney this is your best option.
The consumer laws in New Jersey are expansive and powerful. The Consumer Fraud Act provides for triple damages and counsel fees if you win. This is the only thing that the dealer will understand.