Here's what I do every time they called me, and they have now stopped.
1) File an Internet fraud complaint at the FBI website. Their site is the Internet Crime Complaint Center http://www.ic3.gov/default.aspx
Include the date, time of call, and any details of harassment. Keep these lowlife scum on the phone as long as possible, it may help to establish tracking codes that can be traced.
2) File another complaint with http://www.stopfraud.gov/report.html
No one likes to have the FED after them, especially crooks that know they will end up in jail once caught.
These lame excuses of humans will have their day in prison. Believe it.
Caller: Abusers and losers