I just got valid info today when they called again. I told them that Sierra club headquarters is not aware of any phone calls going out to the public with that number and pressed them further. We are not a Sierra club member so I was concerned as to
why they were representing themselves as such and how they obtained our number. Once I said that I reported it as a potential scam the woman said they were actually calling for senator chiesa office in Washington, D.C.! She said had my husband been home and answered, she would have connected him to senator chiesa's office for a political contribution on the environment. I appreciated her honesty but I asked how and why were they misrepresenting themselves as the Sierra club. She said it was a way of getting access to members of the club without saying it actually was political! But alas we are not even members so they truly are lying right out front. I called back headquarters and left this new info. it must be a way to lobby...I feel it was wrong as the mysterious calls and hang ups for a week was alarming! So do not answer unless you want to contribute to a political cause coming in through the back sneaky door. Thanks for your input too

I have received numerous calls from this phone number. No one there when i pick up either.

They just called me and all I received was a click.  Then no less than two minutes later another call came in from an "organization my spouse supports".  The number was 412-622-7386.  The called id said public interest commission.  We receive from 6-10 calls per day from calls such as these with varying caller id's. So annoying