If you give money to a charity, do it anonymously. If you give your details, they'll call you for more donations in future, and who can say they're wrong to do that?
I got two today. The first one was for daughter.2, and they asked for her by name. A charity called Orbis. I spoke to them, and they said she'd supported them in the past, and they were calling to thank her, which wasn't the whole truth, they also wanted a further donation. So I asked if they could take us off the list of people they phone. But no - they can't. Apparently, only daughter.2 can ask them to do this.
"Oh," I said, "that's a problem. because she doesn't live here. So I guess you'll be phoning here, fruitlessly, for ever?" At which point, they discovered that actually they could take her off their list without her talking to them. How handy! Actually, she's never lived here - we moved here after she left home. So how did they get this number?
That was at 7:30 pm. So, about half an hour later (they time this for when you're eating your dinner, of course) I got another phone call, this time it was the Red Cross. And they wanted to talk to ladysolly. We went through the same process - they can't take her off their list unless she tells them to.
At that point, I'm ashamed to say I told a porkie. With a bit of a sob in my throat, I told them that she doesn't live here any more, implying that they'd just brought up a very sad memory, which I'd rather not be reminded of, sob, sob. But then I had another great idea. "Would you like her new number," I asked. "Yes please," they said. So I gave them the phone number of a serial spammer that I've been trying to deal with.