I purchased a vehicle in AZ about 10 years ago and never got a title for it, the auto dealer now doesn't exist?

This was a small auto dealership called Wynn Company in Mesa, AZ. My dad was the co-signer but he in-up being the main person on the application. We paid off the car in 2 years or so and the finance person said we would receive the title. But never got nothing. My father ped away in 2005 and now my mom is trying to sell the car. Well she went to the DMV in AZ and they told her there was a lien on the car saying we still owned money on it. Now my mom can't get rid of the car and it doesn't work anymore. What can we do to get the title to get rid of the vehicle. Please help