I don't get why they call and just don't say anything.  Then, some clicks later.  I left it on for 30 seconds.  No hang up but silence too.  What is up with that???  What is the purpose???  they call multiple times a day!

Female voice saying "this is not a sales call, do not hang up. There has been a burglary in your neighborhood".
At which point I promptly hung up and went online to my voice over internet phone service website and blocked that numer from calling me again

HIJOS DE LA [***] DEJEN DE CHINGAR VAYAN A CHINGAR A [***] MADRE

100% scam.

Caller ID says "Home Security"; they usually hang up if I answer, or there's just a lot of clicking on the other end. They never leave a message. Once, I did answer and there was a guy with an accent who asked for my daughter, and said he was offering special pet health insurance. I told him she has no pets (technically, they're all mine) and she is unemployed. He hung up pretty fast. The Do Not Call list is a joke. I've added my number to it several times, and these yahoos still keep calling.