Confused By Chapter 7 Exemptions

I participated in a Chapter 13 Bankruptcy for over 18 months when it was dismissed because I fell behind in payments. Since that time, my car has been repossessed and now they are trying to collect $9,000 which they say was the difference between what I owed and what they sold it for. I am also starting to get letters from the creditors that were listed on my Chapter 13 case. I am really confused about all of this. If I couldn't afford my payments to the trustee, why do they think I can afford to pay them all? I don't have a job and don't own a home. All of the furnishings, appliances, etc. in my home were charged on credit cards. I do have another vehicle which wasn't a part of my case because it was leased. However, I was able to keep it and continue making payments. I still owe $9,000 on it. The word exemptions keeps coming up and I can't figure out what they are talking about. What exactly will happen if all of these people pursue a judgement. What would I lose if I filed a Chapter 7? Bottom line for me is: You can't get blood from a turnip, so how can I pay them if I can't afford it?