This is a call center (they have a variety of numbers all starting with 617-591-62XX) that makes calls for a variety of non-profits. If you call one of these numbers, you can choose a "do not call" option from an automated voice system.
Yeah, they called on mother's day. If I remember, they called me for several weeks straight back in Feb/March. I never answered. Guess today it will be 6218...