a flimflam artist
Someone who acts deceptively and tries to trick people. The word "flimflam" is thought to be of Scandinavian origin. I suspect those guys are flimflam artists, that's why they want so much money up front.
n. someone who practices confidence tricks or deceptions on someone else. I don’t trust that flimflam artist at all.
A swindler. Flimflam artist indulged in confidence games in which the victim is persuaded to buy worthless property. These crooks go after bigger game than street hustlers, card sharps, or bait and switchers do because of the time and preparation that their scams require. “Flimflam” has been traced back to a Scandinavian word, although folk etymology has come up with a connection to an early 20th-century New York City law firm of dubious reputation, Flam & Flam.