IRT to phone scammers.  I suggest signing up for Nomorobo.  I signed up for the Do Not Call List years ago, but, was still getting unsolicited calls.  When I signed up for Nomorobo, those unsolicited calls are ALMOST to zero.  Scammers are finding ways to get you to answer your phone.  The Nomorobo is on our landline, so, when we are watching TV, the caller's number comes on the TV screen, but the good thing is the phone rings only once.  That's how we know it is a scam.  Sometimes on our phone, it just says "Incoming Call" with the one ring.  
We notice the calls that are from credit card companies that wants us to lower our interest rates have 808 area code and the number, but, the company name on the TV screen is not from a credit card company.  We do not answer the phone unless we know the person or company, or, we just wait until the answering machine goes on and we listen to the message.  If we know who it is, we answer, otherwise, we don't.  
Sign up at Nomorobo.com.  Good luck.