Reporting violations of the Telemarketing Sales Rule is never a waste. You just have to be patient for results now that scam callers can hide behind cheap VOIP and Caller ID spoofs. Complaints to DNC form a handy pool of intel for law enforcement, something you are all prompted to read about at registration. Those complaints have helped the FTC choke off several credit reprice scammers since 2009.
If you hope for more prompt human assistance, file complaints with the FTC and attorneys general. Individual action through a TCPA lawsuit would be a strong suggestion, if anyone manages to corner one of these scammers long enough.
Here's a link to a site which helps explain the scope of the problem and why the credit reprice scammers are hard to control: