Don't answer it! See:
http://www.ripoffreport.com/r/smart-one-energy-llc/wesley-hills-new-york-10952/smart-one-energy-llc-tricked-my-wife-into-unwittingly-switching-our-gas-service-wesley-813331
and
http://www.bbb.org/new-york-city/business-rev ... 0/#reasonrating

301-728-3106
I received a call and they told me I earned a 10% discount on my gas bill.  The caller ( who sounded like she was from India or Pakistan) knew my address and my name.  When I acted suspicious, she hung up.  I tried to call back but   a recording said that "The subscriber you have dialed is not in service."

At least that's what they say. I assumed it was a scam as soon as I started to ask to verify account information.

This is a Energy Supplier Solicitation call for Washington Gas.

Yes, they hang up on you as soon as you pick up. I agree, very strange.

Received several calls from this number, but was disconnected as soon as I picked up the phone. When I tried to call back, I got a recorded message saying the number is not in service. Very strange.