This number has called me repeatedly over the last week. They do not leave a message. I called the number, which appears as a cellular call, and it went to ICG Energy Customer benefits. They were closed, so I could not tell them to stop calling me. However, there was an answering system that identified them.
They call frequently in the hope of getting me to change by natural gas service from Consumer's Energy. I have told them each time I am not interested. The cell call must be a way to disguise their identity in the hopes you will answer and listen to their pitch.