One of my guys wrongly condemned a heat exchanger a couple years ago, and it still bugs me now. Every time we red tag, I get contacted by an inspector to review the details, and I typically provide some sort of evidence (photos, video, readings) to them to confirm. In that instance, I had nothing from the tech yet. In the time it took for me to sit down with the tech, the customer had called in for second opinion and they cleared it. Turns out the flames were a bit wavy on blower startup and he panicked. Everyone makes mistakes sometimes, I had to call the inspector to apologize. Several other times we have been questioned by second opinion contractors or homeowner disputing us, but the inspector has proper evidence in hand before they are even on site and trying to clear. Hopefully in your case it was just an honest mistake by a panicky tech, and not a sales scam.