I worked as an electrician for a licensed company for a few years out of school. We got calls like this from people when a string of outlets / lights got interrupted. Most times it was due to a recent device (outlet / light fixture) change and a connection wasn't tightened good enough that came loose over time, or a device failure. I've never seen a wire fail between devices , not to say that it never happens. When splices / junction boxes are hidden in walls during a remodel (against code), that's where hunting a phantom interruption becomes bedeviling. A "professional Electrician" should've been able to hunt down an interruption or a failed device within three hours.
As far as finding violations and making extra work, threatening to call in the county / building dept., I call B.S. on that one. That's where I'd go nuts. No contractor would want that kind of a reputation, ever. Could you imagine him finding that all over the internet someone posted telling everyone how super safety conscious he is, that he'll report any & all violations found to the city while working on your home if you don't let him fix them on the spot. How long do you think he'd be welcome into any potential customers homes or businesses? In this day of the internet where anyone can leave a bad review, especially if they have an ax to grind, you don't want to be in that mix there as a contractor or any other kind of business.
Sure we'd find other problems, some nasty, we'd mention it to the home owner verbally but would never think of threatening "violations" for extra work. You don't need to protect your livelihood / license that way. If your sent to find a short, you're looking on that circuit, not all over an attic, you're not there to do an "inspection". There is no assumption that you should've saw something should a place burn down even the next day. Fires are rare, most are caused by people. Even in the nastiest places with all kinds of violations, they are still open buildings & homes that are standing without issue or repairs.
I think you got screwed by both, they saw you as easy pickens being 800 miles away and unfortunately you kind of are, especially when you are notified after the fact.