Here is the situation, as briefly as possible: 2010, moved out of house that I shared with ex, filed police report about abuse, he was arrested, convicted of DV. I did not have a chance to get my stuff, including my birth certificate, naturalization document, passport, pink slip to car, tax documents, and social security card. In the following months, I was too afraid to go back to get them by myself, but I had warrants so I was also afraid of being arrested if I requested a police standby. When I finally got the nerve to go there myself, he didn't have them, or he threw them away. Later, he told me he would give them to me if I paid him money. I don't know what the truth is, but what can I do now?
You need to do what should have been done originally. Contact the police. The problem is you have now let a tremendous amount of time go by so your prospects of getting useful assistance at this point are considerably diminished. Most if not all of the documents that you mention can be replaced, but it will take some time and effort. Your choice.