Seems like those JWs were just inexperienced, or at least unprepared.
Standard JW response would have been, "Oh yes, that was true in the 1st century, but not now! You see, that gift, along with the gifts of tongues, prophecy, miraculous healing, resurrecting the dead, etc., ended with the death of the apostles. See what it says here in 1 Corinthians chapter 13..."