I have received more than 550 "lower your credit card interest rate" calls on my unlisted - Do Not Call registered cell phone. They are now calling 4 to 5 times per day. These calls have been increasing ever since the FCC has taken action against the 9 robocall spammers.
Slapping them with a fine that they do not have to pay isn't going to deter them at all. You need to go after them in CRIMINAL court for the advance fee fraud and the identity theft.