DON'T ANSWER UNKNOWN CALLS. DON’T HAVE YOUR NUMBER REMOVED! When you press the number to have your number removed, you confirm that your number is a working number and then they sell your known active number to another scammer.
ROBO CALLS: Each area code has 9,999,999 numbers times that by 800 possible area codes. The program starts calling every number that it can in succession. So they don't need to buy or obtain lists from anyone so DNC does not work. The authorities can not or will not help either.
So, just block them, and continue using this great site for information to be in control of your own home and cell phone calls. If it turns out that you did not answer a call from someone you know (number not on this site), just call them back. No problem. MY HOME PHONE (Panasonic Link2Cell Bluetooth® KX-TGH263B LCD/2 Handsets) BLOCKS 250 NUMBERS AND THE ADDRESS BOOK HOLDS 3,000 numbers and the phone talks to you and says spam from across the room (like if you are up on a ladder). I save each call as spam and don't answer it. Right now I have 98 numbers saved as spam and still have room for 2900 more.