I'm not pulling for the NSA, far from it. But they need some good PR and I have an idea to offer.
There are reportedly 210 million phones on the Federal Do Not Call list and that list is certainly available to the NSA. And there must be well over 210 million junk calls daily to those Do Not Call numbers.
It wouldn't take much metadata to find the handful of companies violating the statute. If NSA put that bit of data together and turned it over to Justice Department for prosecution, they would be doing us a big favor and (somewhat) repair their image.