Dear Upset: The DNC law is for law-abiding people. These telemarketers, etc., who call incessantly, are not law-abiding people. From having followed complaints about nuisance phone calls since 2007, it is my opinion that it is the robo-callers who have the lion's share of causing aggravation. Do see here at 800notes the Forums and the Latest News postings.
Simply put, don't pick up any calls with names and/or numbers you don't recognize!