Used Cars: used car contract, car contract, finance officer

Question
I purchased a used car on 8/17/07 the agreed price was 4500 after the tax, title etc... the price went to 5002.10 I used the credit union to finance 4500 the dealer received the 4500 check when I went to pick up the vehicle the finance officer stated that I didn't owe any additional money and I signed for the car on 9/17/07 I received a call stating that I owe them 500 more dollars because of THEIR mistake what can I do legally? I still have temp plates the car is out of state.

Answer
This may be out of my area of expertise.  I am familiar with Oklahoma laws, and I am not sure really what you should or should not do.  Here we pay the taxes and title after the purchase, but within 30 days of purchase.  If you have the title, and the car is officially yours, and they are just trying to recoupe from their mistake, I dont think you would have to do anything.  This may be more of a moral issue as opposed to a legal issue.  I mean, if they made the mistake, their loss...in my opinion.  I promise if something happened where they owed you $500 that you were unaware of, they would not call you and offer it to you...in my opinion.  There may be some places that would, but I dont think most big dealerships would.  Again, I dont know if they can interfere with your titling of the car and paying your taxes or not, but if not..I wouldnt worry about it.  Their mistake...their loss.  Here, if you have the title, or the credit union has the title, and you have signed everything making the car yours....I dont think you will "HAVE" to pay them.  I have worked in big dealerships, but for good people, if we made mistakes...we just owned up took the loss, and tried to better our processes.  I am not sure if this answers you exactly, but I hope it is a little helpful.