Advance America Line of Credit

I have a question about Advance America's line of credit.

I have an account with them and I am using what they give me, but here for some reason they are now saying that all money is due and I don't know what is going on. Going to call them tomorrow and find out. Anyway my question is I had to use my car title as collateral. It's not my main car, it's really a junk car as it don't run.

If I don't pay I know the repossess the car. What happens then? Do I still owe them money? What's the deal and how does it work. I'm going to try to see what is going on and get things straightened out as I like them so far and they've been working with me in the past. I just don't know what's came up with this full payment thing.