I too, have recieved a call, from a different phone number, from an individual claiming to be working for Washington Gas Co., as that was the message left on my VM, along with call me back (don't remember name) to discuss your account.
After calling Washington Gas directly and giving them the phone number that appeared on my C.I.D., I was told that no contractor with that particular phone number or name was working for them and that "Nobody" from Washington Gas would be calling me/you and asking for any personal information, IE: Account Number.
Never give out any Personal Information to anybody who contacts you asking for such information.
If my C.I.D. display's any of the following, Unavailable, Unknown name and number, Out of Area, Private Call, then I let my VM take care of it. Usually when no message is left on my VM, I know that ROBO dailing was in progress and that will indicate to me, that it was either a Telemarketer, Solicitor or worse, a Scammer.

Caller ID says Maryland.  I don't answer calls I don't recognize. I'm sure it is a scam.

Been getting calls several times a day from this number. When I pick up there is no one on the other end and then the call drops after several seconds. This has been going on for several weeks. Just today when the call came through there was someone on there end! They could hardly speak English but said they represented "Washington Gas" and started asking for my personal information. I of course did not give it to them and asked for their name and phone number. They did not give a name but started to give me a phone number and hung up half way though.