Inspired by a post I just saw about someone emailing the recruiter that wasted an hour of their team waiting for an interview, don't just email your original point of contact!
If someone is in a position where they can't afford negative attention, taking a few extra minutes to CC their supervisor, manager, and higher ups you can find connected to their site, you'll have a better chance at long term repercussions on their side when you callout their errors.
Just had a friend do that at Disney recently, calling out their managers and their supervisor, and then CC'd the entire upper management in their chain. I can tell you it certainly had an effect, and had multiple managers end some fairly shitty behaviors.
So don't just have one point of contact, ever. They'll hold each other accountable.