Thank you for posting all of this very helpful information!  I actually spoke to the recording -- it's very smart and knows how to answer, to a degree, but you can tell it's a voice-activated recording, and it was a little scary.  Glad I didn't donate.

Received a call to our land line from this number today (28 Dec 2016) at 11:23 am (Central Time.) Caller ID: United Breast C. (United Breast Cancer Foundation.) We have received a couple of calls from this number over the past 2 weeks, with no message left. This time I answered so I could tell them to take our number off their calling list. I got no reply when I picked up and said "hello." I said "hello" a 2nd time. Still no voice (recorded or real) on the other end. I held on and eventually heard the click of the call being disconnected. Then, the dial tone started. We live in Missouri. I do not find the organization listed as a registered charity in Missouri. See: https://www.ago.mo.gov/divisions/consumer/check-a-charity . I suspect it's a scam.

Received another call to our land line from this number today (22 Feb 2017) at 8:35 am. Caller ID: United Breast C. Didn't answer. No message left.

calls daily,  no message, I have not and will never give to United Breast Care

These idiots called at EIGHT O'CLOCK IN THE MORNING!!  Hung up after 2 rings.
This is harassment!!