Send them a blank card, and don’t write anything inside it.
If they ever call you and ask you about it, just let them know that God wrote some very important words in there, but only followers of the one true religion can read it.
No, other religions feature gods dying so the corn will grow, or gods nailed to a tree so they can learn to read and write and pass it on to men, and where they talk about afterlives at all, you get what you’re given - deities don’t go around offering themselves up as substitutory sacrifices to get you into Valhalla or Elysium or anywhere like that, and from what I remember of the Tiger Balm Gardens when I was an impressionable child, the Chinese Hells aren’t nice at all. As to the other, my spelling could be way off and I’m completely brainfarting on the religion or the language, though it sounds vaguely South-East Asian to me.