I never open link; I usually keep phone in headboard to ignore it.  Above comments indicate people still open lines instead of ignoring.
Ignorance was bliss since robo callers will kick back to once a month, then every two or three months.  They own multiple phone numbers so 'blocking' is a one time fix.
Heard 'hacker' other day on FNC and he said you'll never stop them, they're the cockroaches of the phone lines.
IF you don't recognize number of area code; ignore, ignore, ignore.
Then you can type in number like I did now and decide whether to add to comments.

Pax Domini

Easiest way to eliminate these bothersome callers...if you have a smartphone, download Mr. Number.  Add them to the Block list, and have your phone pick up and hang up every time they call.  Sorry if you have an iPhone...the Nazi's at apple don't think you should be able to do this on their iPhone.  You can only send them to voice mail.  

they called my cell phone,how they get my number,rip their fingers off!

Claiming to have my credit card info and wanting to help me lower my interest rates. First off I have no credit cards. Secondly, they never asked for my name but kept insisting that they had my info. I informed them that I have no credit cards and I am on a do not call list and they argued with my trying to get my info.
THIS IS A SCAM. DO NOT GIVE OUT YOUR INFO FOR THEM TO VERIFY. THAT IS HOW THEY ARE GETTING YOUR PRIVATE INFORMATION.

How do you do that?