Constantly calls. No one speaks. They hang up.

This is a SCAM.  Women called claiming to work for Duke Energy with an offer of a rebate if I answered a few questions, but needed MD to provide my account number to get started or even send me information in the mail.  I fortunately couldn't locate it even though she had "all the time in the world" to let me search.  I finally got frustrated and told her I wasn't interested.  I called the number back.  It's First Energy Now.

Phone rang... I answered... nothing.  Not even the sound of breathing.  *click*

Calls multiple times a day and never leaves a message. May have been a coincidence, but seemed to coincide with Twitter/Facebook activity, as if they expected me to be home after I had tweeted from my cell. Got a "Hello?" once on the machine and then they hung up. I blocked my number and called back. Seems to be some sort of call center, but it has been 5+ minutes now and no one has answered. Only hold music and a voice repeating that I will be transferred to the next available agent.