I received a call from that number.  They left a message saying they needed to talk to us about our Duke Energy bill.  I knew there shouldn't be an issue with our Duke bill but I called the number that was left on the message.  It was a sales pitch for Future Now Energy.

This person keeps calling about a natural gas bil...There has never been natural gas on the property this individual is calling about. I called back busy at first then just rings.

Never picked up - I guess they will keep annoying me. Nice to have a do not call list. All the sc*mbags ignore it (like these guys).

Picked up this time - they are one of those energy resellers
We don't pay our energy (apartment).
Told her in a not so nice way - to stop $#$% calling.

I knew this caller was a scammer since she said she was from the National Grid which I know is a generic term.  Besides my building does not even have metered gas/electricity so when she told me it was about my account, I knew it was a scam artist.  

Anyway, to play along with her.  She told me it was about problems with my gas bill.  I thanked her profusely and said she called at a great time.  I had just eaten some burritos for lunch and had lots of excess gas.  Then she said "No sir, it's about your gas bill".  I said "Ma'am, don't worry about the bill as I understand that if I had excess gas from eating burritos that I should be charged.  Besides my roommates won't even talk to me anymore."  She kept on insisting that she wanted to talk about a gas bill and I kept on repeating that I had burritos for lunch.  I then offered to put the receiver next to my butt if she wanted proof of my excess gas.  She then hung up.  Don't think she'll call again