How do I get them to stop calling?

Repeated calls from lady speaking very very poor English. Could not understand her.

For several years I've given $ to this charity that uses the donations to purchase books for sick/injured...(hospitalized??) children; but I'm not so sure it's as 'legit' as I'd like to think. A word of warning to those of you who don't want to commit to their 'cause' for the long term; they'll call you every year for as long as you use the phone number at which they reach you. I hope that I'm wrong, and that kids DO benefit from this becauseI've been giving ~ $45 per year for close to ten years.

This number left a 3 min message that all you hear is the clicking of a keyboard in the back ground.

Been getting this number on my call display last couple days so seached and read posts here. Finally answered the call tonight. Could barely understand the lady. I asked for their website adress because all legit charities have website and she hung up on me.

I just received three minutes of classical piano.  I suspect three minutes is the maximum voice mail message...