The number calls me, I say hello, there is a period of white noise, then a loud beep, and a recorded female voice says "goodbye". Then white noise. Eventually it hangs up. I got the name of this company by calling the number back, and this is a very busy call center. The man identified the company as Oasis Energy, but was nice enough to take add my number to the do not call list.
Caller is from Oasis Energy trying to sell me a lower at over 9 cents per Kwh which turns out to be higher than the rate I am currently paying. Besides that, there's a $5.95 monthly service fee and termination fees if I were to cancel the plan at a later date before the contract expires. I am on the Do-Not-Call list but this doesn't seem to stop them.