1) Stranger approaches you
2) They tell you some things
3) They ask for money
That process looks like a legitimate cold-calling salesman, but you can treat them the same way and not miss out. After step 2), assume everything they said is possibly a lie and go find the actual person/organization you already know and trust and contact them yourself to do whatever it is. If it's not somebody you already trust, as in this case, then abort.