Is it legal for a charity to contact you if you have set up an automated message asking them not to?

I am told that charities must, by law, take you off their list if you ask them to do so. A couple I know has a system set up on their phone that plays back an automated message when someone calls. It says something along the lines of "If you are a telemarketer, please hang up and take this number off of your call list." Would it be illegal for a charity to solicit to them?