I had this happen when I lived in Denver, but with windows. Someone came knockin', claiming they had authorization from the city to inspect my windows outside AND in. I made it clear they should vacate my porch promptly, went out and took a photo of their plate (while they tried to block it), and called the police.
As a contractor always buy your own materials for repairs if you can or pay the supplier directly. And make a payment schedule to start the first day when they show up. Pressure to act quickly is always a bad sign. So wrong.
Never let anyone on your roof to "inspect" your house. They could go on your roof and use a coin to start scraping little circles that look like hail damage. Even the insurance inspector from your insurance might be friends with the guy going on your roof and causing the damage. I've almost become convinced everything is a racket. I don't trust anything anymore and you shouldn't either. Someone calls you, don't answer.
