Your phone rings but you don't recognize the number on Caller ID or your phone rings only once. You let the call go to voicemail but whomever is calling does not leave a message. SOUND FAMILIAR? THIS IS WHAT IS GOING ON:YES, THIS IS A ROBOCALL USED TO DETERMINE IF YOUR PHONE NUMBER IS A VALID, WORKING NUMBER THAT IS BEING ANSWERED BY A REAL LIVE PERSON. IF YOU ANSWER, THE TELEMARKETERS/SCAMMERS WILL THEN PLACE YOUR NUMBER ON AN “ACTIVE/LIVE/WORKING NUMBER” LIST AND YOUR NUMBER IS THEN SOLD TO OTHER TELEMARKETERS, SCAMMERS, AND DATA BROKERS. HERE IS SOME ADVICE:***First and foremost, DO NOT ANSWER CALLS FROM NUMBERS YOU DO NOT RECOGNIZE!*** This is your best defense against further unwanted calls. Period, end of discussion.DON’T EVER CALL THESE PHONE LICE BACK OR ACKNOWLEDGE THEIR CALLS IN ANY WAY (i.e. press 1 to remove from list, press 2 to speak to someone, or calling the unknown number back, etc.) as they will put your number on an "active/live/working number" list and you will actually get MORE calls from other scammers. Check out the November 2015 issue of Consumer Reports for more information on protecting yourself and the February 2016 issue of the same magazine for info on scams similar this as well as the notorious IRS SCAMS. KNOW YOUR RIGHTS AND THE LIMITATIONS OF THE DO NOT CALL REGISTRY BY GOING TO THIS WEB SITE https://www.privacyrights.org/telemarketing-how-have-quiet-evening-home Also, IF YOU CALL THE NUMBER BACK, IT WILL BE VIEWED AS YOUR ATTEMPT TO DO BUSINESS WITH THE “COMPANY” that contacted you. What does this mean? IT MEANS THAT YOU ARE NOT PROTECTED UNDER THE DONOTCALL.GOV umbrella for that “company” and that particular “company” (scammer/telemarketer) you called back may then LEGALLY CONTACT YOU FOR THE NEXT 3-18 MONTHS and there’s nothing much you can do about it.ALSO, THE NATIONAL DO NOT CALL REGISTRY ONLY COVERS TELEMARKETERS AND NOT ALL SOLICITATION CALLS ARE COVERED BY IT. The following type of calls are EXEMPT from the DNC Registry:•CHARITIES•INFORMATIONAL CALLS•SURVEY RESEARCHERS•POLITICAL CAMPAIGNS•COMPANIES (OR A COMPANY’S AFFILIATES) WITH WHICH YOU HAVE AN EXISTING BUSINESS RELATIONSHIP (EBR)•COMPANIES TO WHICH YOU HAVE GIVEN WRITTEN CONSENT TO REMAIN ON THEIR CALLING LISTJust BLOCK the number and go on with your life. There are FREE apps for both Android and iPhones that you can download in order to block further calls from that particular number. Landline customers may be able to use the FREE service at www.nomorobo.com . Also, be sure to HAVE YOUR PERSONAL INFORMATION REMOVED from information broker sites such as www.spokeo.com . There are many, many information brokers so you will have to contact multiple companies individually. Be sure to check these information broker web sites every 6 months as you may find that your information is periodically put back up.Helpful Note: I downloaded the 360 Security app from Google Play and continually add known scammer phone numbers into it to keep it up-to-date. I also downloaded YouMail from Google Play store and set the outgoing voivemail message to the "doo-doo-doo . . . the number you dialed is no longer in service . . . " message. So now when a known scammer/robot dialer calls my phone, the 360 Security app immediately intercepts the call and forwards it to my YouMail app, which then immediately plays the "doo-doo-doo . . . the number you have dialed is no longer in service" recording that we are all familliar with. The tones at the beginning of the Youmail outgoing recording makes the robodialer automatically disconnect the call and ditch my phone number from their system. The result is that my phone never rings when the call originates from a known scam number, robo-dialed callers are unable to leave a message, and I get fewer calls from other scammers. This configuration has changed my relationship with my phone! Please note that if you set up the same 360 Security/Youmail configuration as I have, be sure you notify friends/family/people who you want calls from that despite what your outgoing voice mail message says, your phone is in service and they will be able to leave a message at the end of the outgoing message like normal.