Same experience - spoke illegibly, left a reference number, and said to have a bill handy.
Ditto - thanks for this site. Calls like this can catch you off guard.
Scam! Super pathetic. I received the same note - "Hello this is Rebecca Davis. I left you this message regarding the supply charges on your electric account. Give me a call back at 718-682-3193 and have a copy of your electric statement handy to review your reference number is NY556987." Even the reference number was the same....they couldn't be a little more creative here?