Answered thinking it was a friend and immediately heard call center voices.  I immediately went into the "take my name off your list I am not interested" and the woman said this is not a sales call and became very verbally aggressive.  I should have just hung up but then she said she was offering a "free energy audit" and that was when I blew up.  I told her I had received over 20 calls from different phone numbers offering me this free energy audit and what part of no did they all not understand and simply just hung up!