Caller ID says "Walnut Creek CA".  They leave a "message"; it sounds like someone moving around in a kitchen.

I call back after hours (using *67 to block my number).  The voice I hear sounds blue collar, non-professional and has an American accent.  I hear, "Hello.  We tried to reach you on behalf of the non-profit shareable organization.  If you wish not to receive any calls in the future, please, leave your area code and phone number slowly and clearly, and we'll be glad to remove you from the list.  Thank you and have a great day." (I never do this as it can actually make things worse.)

Their "name" seems way too generic.  I'm guessing this is a scam organization that wants your money to supposedly support non-profits.