I would have told them to not post that apology, and they should file a small claims action in Champaign County for the charter money. Reasonable and detrimental reliance after Iowa sent them the tickets, etc.
It's stupid of them not to set up fake entities or mailing addresses near other B1G campuses in advance if they're going to use group discounts, but it's not fraud unless this public university is discriminating on the basis of what is ultimately speech and making assumptions about who's using the tickets.