OP, as many have said already, NCNS's are common in this industry.
There are some providers out there (you know who you are) who are well-reviewed and have a long showcase that drones on and on and on and on...about all the Do's and Don'ts they expect you to abide by if you're fortunate enough to see them and how important good communication and timeliness is for the appointment... yes - even some of them can be FLAKEY.
"Hypocrite" also comes to mind.
That's the industry, brother. Get used to it.
But.. for every flake, there are a dozen gems.
My advise is to forget about it and move on. Let the flakes be the flakes and find yourself a dependable ATF.