Somebody was paid off. You have grounds for a lawsuit.
While "you can sue anybody for amything" is a common mantra, it isn't really true.
You have to be able to show how you were damaged or harmed by someone else's actions. In this case, how much damage or harm (in lost money) was caused by a business poor practice? Give a dollar amount. Where/how did that amount of damage occur? If a downpayment was made via credit card, and that charge was not paid by the plaintiff, OR could be reverse charged by the credit card company what is the damage?
Then the court will ask did the company make an effort to fix the problem? In this case yes, they offered another vehicle.
The other point here is the question of is this a rare happening in that industry? No, it's not. It happens enough that it may be considered a standard practice.
These types of things are infuriating to people (consumers) who are good and honest people. And these things are why car dealers are largely despised.