As someone who has worked in multiple call centers, one thing you need to realize is 90% of established Charites and Product/Service Companies do not make solicitation calls in house, they delegate to call centers filled with callers that do not GAF about the charity or company & are getting base pay so here's how to make them stop.

If a Charity is calling you 99.9% chance they are asking for more money, so don't bother having a conversation, as soon as they mention the charity, simply say "I do not wish to donate more, add me to your do not call list" then hang up, nothing more nothing less.

For Marketing Calls just say "Add me to your do not call list" then hang up

Do not Ever hang up as soon as they introduces themselves

Do not say you are busy

Do not say you aren't interested

Do not say You can't afford to give/buy

Doing any of these things will result in your number being added to a list for redial/ for further solicitation campaigns