I understand your disappointment but if the usher 'shooed' you, it was only to get to the next person in line. That didn't mean you had to leave. You could have gone to the box office to see what was going on and then made your decision...see the show, get a refund, try to tickets on another day. I don't believe you have to be a Broadway Insider to understand that if you are confused, you should ask a question.
My second point of confusion relates to what you seem to think is a conspiracy to charge you a lot of money and then bail on the performance. Performers sign contracts. Producers expect them to show up if they can. If there is a planned vacation for a performer whose name is above the marquee, it is usually noted on the ticket site but if someone is sick, or if there is a personal obligation that comes up at the last minute, the cast is allowed to take a day off. They are human. I worked in a regional cast years ago where the flu spread through the cast like wildfire. It happens.
Respectfully, I wonder why you would pay that kind of money, be that disappointed and just walk away without asking a question, and then seek advice and context from a Broadway chat board. I think we all have to exercise common sense at these times in our lives. .
"Life is a lesson in humility"