No, having an unlisted number does not help. In this age of technology anyone can get your personal info if they want it bad enough.
These criminals use auto dialers, not much FCC can do. Your best bet is get a call blocker and don't answer or return any calls you do not recognize.
I feel your pain
I agree I am on a do not call list too. I get so many spam numbers calling I don't even like using my cell any more. I had my home phone removed for the very same reason.