She gave my wedding dress to someone else

Be

I went wedding dress shopping today and the lady brings in a few dresses at a time. I found "The Dress" but was encouraged to keep trying on more. I was adamant on that dress, but also, it's not going anywhere right? It's in my dressing room.

Come back later to try that dress on again and another worker TOOK that dress out of my fitting room and had another bride try it on who decided it was final and her dress. That was the last dress left (I'm on a budget and went to a budget store.) the dress was $500AUD clearance. I am absolutely devastated, there is nothing they can do about it apparently. I am heartbroken and left without the dress I wanted. What do I even do.