CA. How do I get the car out of my name?

[just some girl]

So I sold my old car to someone from cragislist. I gave them the pink slip and they gave me the money. .. that was that. They said they were going to the dmv to put it in their name. Well... I find out a few months later they didn't do that. I received letters in the mail under my name saying the car needs to be reg and smogged. I don't have this b.i.t.. c..h.e.s. name or information, so the dmv said i can't really fill out a release of reliability form. I could report that btch stolen. and I guess get the car back.
What do i do?