We get the same calls. Also, I get e-mails from companies I never heard of. It tells you that if you want your name taken off the list, to "click here". I do that and you have to leave your e-mail. I'm always afraid that, when I do this, they'll send my e-mail to other organizations.
Also, when I get requests for donations in the mail, and I send one, I get requests for them about every 3 months, which makes me not want to donate to them ever again.