Here's the answer from Better Business Bureau:
As you'll see from articles, NEVER answer and don't trust caller ID. but if you do answer, give them nothing and push no buttons. The robo-caller wants your banking/financial info to phish for your CC number or SS number.
My tech-savvy sister had this happen fairly recently. 't's a nother wrinkle of phone scam. This newer robo-caller (offshore) has the ability to do spoofing ....of numbers...believe it or not,...even your own.
When, and if, they connect with you (generally they hang up or wait for you to pickup), it'll be some telemarketing spam... or some fishing scam that tells you they're the IRS (foreign accent) and you're going to be prosecuted by IRS / Treasury and the police will be contacting you.
Be aware that IRS protocol and regulations are set up so that they never would contact you in such a manner.
The trick is never to answer the call from a non-ID or strange number. They'll leave a message if it's a real call. Though, admittedly, it's kind of shocking to see your OWN number come up. Technology should be set up to block such an occurrence.
If you Google this, FCC is aware and is working on this with carrier (Verizon, AT&T etc.) but don't hold your breath for the solution any time soon.