Without putting too fine a point on it, yes, that is entirely the norm. I'm pleased you got your first taste of the Envoy experience before even interviewing. The reason they are "unable" to change your flight is probably because it would require 10 or 15 keystrokes from one of our back office eaters.

You need to make peace with you and your well-being not being valued by the company if you want to make it here without burning out. This isn't necessarily a big deal - we're a unionized labor force, we have an adversarial relationship with management 99% of the time (1% of the time they give us cheap pizzas in the break room), and only receive human dignity when we can force them to give it to us in highly specific terms in the contract by crushing or tricking them in negotiation - and even then, they sometimes operate in open defiance of the contract, or renege on deals they signed.

Your post sounds like you expect Envoy to give you some kind of premium experience. I urge you to look elsewhere if that's really what you want, you won't get it here, and even if you get it from recruiting it's going to go away sooner rather than later once you have an employee number.