They peddle alternate energy supply services. The way they work it is that they guarantee, temporarily, a lower rate. Once the guarantee expires, you're at their mercy.
These scammers have been calling me quite often lately, Call ID says "VOICE NETWORK I," saying it's about my utility bill. Usually it's a recorded call and their machine leaves a message on my machine. This time I picked up and pressed 5 to talk to a rep, who said she was calling from the "Utility Services Company" located "here in New York." She sounded sincere so she must have been new, or an unusually accomplished liar. They were calling a number that is registered with the FCC "do not call" registry, so they are definitely a scam.