It's an energy company. They call and no one is there if you answer, but if you call back, you'll get a recorded message that will allow you to enter your phone number on a company do not call list. Just did this 5 minutes ago, so not sure how well it works.
This number has been calling me 3-5 times per day, day and night, for several days. Like the poster above, I called the number to see who/what it was & it's an alleged energy co. I added my no to their do not call list. But, they still keep calling!!