Who called from 3215949410

No answer. Just dead air.

Wife received a phone call from that number, setting up an appointment for free in-house energy audit to save money on electric bills. Called it back and received "not in service" message.

Did not leave a message.

Answered phone with no one there, called back and got message that the number is not in service. Can't stand these freaking calls.

Just got a call from this number, its happened a couple (few?) times over the last few weeks. No one responded when I said hello and it disconnected after a few seconds. What is the point of these calls? To see if anyone is home or not?