The next time they call just answer the phone in this manner and they will stop;  

If it is a recording let it play and press any number it asks for to  speak to a human being...then ..say,  "This is(your states) District Attorneys Office, how may I direct your call?"  they will immediately hang up and you won't get another call from them.

THIS SEEMS TO WORK QUITE WELL FOR ANY TELEMARKETING CALLS YOU MAY GET

This is a  firm marketing insurance leads

Ahhhh.....A new number to call for the same old home security scam. They don't start out with the ominous FBI warning though. Just that you qualify for a free home security system.