Phred's suggestion should work. During the election process last year, we got a call like that from McCain. I called the number back, and got the recording. Left my number - never received another call.

As for the rest of it, call the American Diabetes Association and firmly state you do not want them to share your address and/or phone number with ANYONE!!

I had to do this with another charity. It's a darn shame these places don't ask you if you want to opt-in, rather than making you opt-out.