Good idea, Nammu.
Hubby and I have caller ID on our landline phone. It even identifies robo calls and scam calls. That helps a lot. And I don't answer calls from people I don't recognize or from 800 numbers. We also can block calls and we use the "do not call" procedure, I am also very careful about who I give my cell phone number to--only friends and relatives--not even doctors' offices. All that sure helps.
I even limit my facebook page viewing and never accept friendships on there from people I don't know personally.