Can't void car contract 1 year later

Dear Terry,
What voids a car contract? What if I never got approved for the auto loan at the time I drove the car off the lot? I signed the papers for my interest to be 9.9 percent. But after running my credit, it came to 14 percent.

It's only been 12 months since I bought the car. Is there anything I can do to return the car or trade for a cheaper one?
-- Shana

Dear Shana,
The short answer is there's nothing you can do to void the contract 12 months later. When you were told that the interest rate wouldn't be what you expected, you should have immediately returned the car and walked away.

You certainly can trade the car in, but I suspect you owe far more than you'll receive on a trade. Stick with the deal until the loan balance falls below what the vehicle is worth and then trade.

Here are this week's reader questions:

• Save big money by adopting 'orphan' car • Can I trade a truck if I'm behind on payments? • What voids a car contract? • Should I take out a loan to boost my credit score?

If you have a question for Terry, e-mail him at Driving for Dollars. Save money on your car -- sign up for Bankrate's new weekend Car & Money newsletter.