So then I said, "Okay, I need you to do an LV," which means line verification, which is asking him to identify the phone number. He does this by dialing a special number that reads back the number he called from. He doesn't know anything about if it's an unlisted number or that it's just been changed, so he did what I asked and I heard the number being announced over his lineman's test set. Beautiful. The whole thing had worked like a charm.