I gave once, believing in the cause of education. My contact information has been passed around like a piece of fresh meat. I receive a relentless stream of expensive mailings and phone calls from all manner of organizations under the National Relief Charities umbrella. One asked for money for blankets for the Indians. On checking, I found that 25% of money raised goes to more fund raising.
Efforts to be removed from their contact list have failed. Do not make eye-contact.

They claim to be top-rated by Great Nonprofits, which makes this organization suspect as well.