I came a cropper on the phone

Couple of days ago I answered the phone to an obvious scam or annoying sales call, and I was ready for it. Something to do with my insurance for stuff I haven't got.
"I'm glad you've called," I said. "Tell me, have you let Jesus into your life?“
They usually hang up at that point. But this one wanted me to tell him about Jesus. And I regret to say so but I was quite tongue-tied about how to continue. If I'd thought ahead, no doubt I could have come up with something suitably fanatical but I had nothing. Nada. Zilch