We voluntarily returned a vehicle due to a family problem 6/2011. My wife has a letter that the vehicle was sold 3 months after the return but

Just because you surrendered the car that serves as collateral for the loan doesn't mean the loan goes away.  It seems clear that the sale of the vehicle didn't bring enough to satisfy the debt. Thus, you still owe the difference. In my experience, when someone surrendered the vehicle, there was usually some sort of work out or agreement about the remainder of the debt. Most often it was accelerated so it all came due immediately, or upon surrender, instead of the usual monthly payments. At this point I bet the dealership has the right to do so under your agreement. Contact the dealer (or whomever is servicing this debt) to work it out. Otherwise late charges and penalties will continue to grow.  Be sure to obtain in writing any evidence of modification of the terms of the agreement or forgiveness of the debt.