Caller ID said 'NOT IN USE'. I almost laughed. Someone chose that one. So, since it is not in use, I picked up, but said nothing, and was responded to in the same way. After about 20 seconds I just hung up.
Got the same robo call from this company even though I am registered with the federal Do Not Call Registry. I filed a complaint with them; if enough people take action, the FCC may go after Energy Direct (417-800-2539). The registry is at www.donotcall.gov