Caller ID says "Unknown Name". Anyone know who this is?

Never got the name of the company, but it's a pitch about changing energy suppliers.

I have been called numerous days in a row. When the phone is answered it just sounds like silence, as if the phone is muted.

Calling about your utility rates. Have to answer phone right now because of medical related calls. :-p

Called in the evening.  Woman sounded somewhat uneducated using phrases like "it don't cost ya nuthin" trying to offer me a fixed rate electric bill from something called Clean Energy.  I said "no thank you" and she hung up.