The current caller ID system is incredibly broken- I'm getting 3 calls a day to my personal cell phone from the same scammers and have not been able to get their real contact info. After watching all these TV shows with the 'hang up within 10secs or you'll be traced!' I expected AT&T to be able to help me out. No dice.
Unfortunately the phone #'s are always random and AT&T just wants to sell me a service that allows me to block up to 30 phone numbers. But they're calling from more than 30.