It never ceases to amaze me how many people don't understand that apologizing costs them nothing, and gains them much. Because she was not willing to simply say, 'I'm so sorry' we made a mistake,' you are considering posting bad reviews about their park, which will impact their business for years to come.
I think the tax evasion / pocketing cash / no records so the next shift doesn't know you exist story is the most likely explanation for what happened. And who would have noticed the scam, if the lady up front hadn't been such a butt about it?
They are making all kinds of customer service mistakes.