ComEd is warning customers about scam artists posing as employees. According to Channel 7 in Chicago:

ComEd reports a 260 percent jump in the number of scams between last November and December.
Scammers contact customers by phone and in-person to tell them their service will be disconnected unless payment is made.

The utility says small businesses and other customers have been contacted by phone and in person. Sometimes the scammers claim a customer's billing cycle has changed and an immediate payment is required.

ComEd advises customers who think they've been targeted to contact the Illinois attorney general's office. Or you can call the company itself for verification about your account.