Thanks for the question.
I'm sorry to hear this has happened.
First, i agree with you that they should honor the contract and anything other than that is a breech, which could make them liable to you. Furthermore, they, along with the dealership sold you the vehicle and there may have been illegal sales practices to entice you to take the loan in the first place.
The good news is your credit shouldn't be affected by this.
Now, that being said, I can't believe they would sell you a car, then sell you financing, then let you drive off, and then have you make payments to the contract, and then lastly force you to give the car back. I can't imagine any judge in America ever allowing this either.
Follow these steps and put the pressure back into their court.
Contact a non-profit agency to arbitrate this matter. Arbitration is when a neutral mediator hears both sides of the story and then makes an impartial decision based on the facts. This process is very inexpensive and I don't think you will lose.
Here's a link:
http://www.adrforum.com/
Also, you can contact a local attorney and have him send out a demand letter to the finance company and the dealership to cease harassing you. These letters are inexpensive and usually get the job done.
Remember that you are in the right. Follow these steps and you should get your issue resolved.
Regards.
Financial Advisor
15 years expertise in all ares of personal finance, including credit cards, mortgages, real estate.