phone rings, no one is there   or
phone rings only once and then call ends

I got a call from someone who said they were representing Com Ed and were going to give me a discount on the next 2 months of my bill.   I asked them if they were Com Ed and he said they were a sub contractor.  I asked him if we were using their services or some form of energy broker trying to weasel their way into my business.

At that point I told him Con Ed could call me directly rather than some shifty sales organization and hung up.

Seemed like a scam.