Unhappy

I just need clarity on what the process is when I search for an item online. I found a dress online and they had 3 in store I went to that store and I was told they don't have it. But the lady later asked for the code only to find that they actually have 4, but they were in a box and apparently they can't open the box for me. So I just need clarity what is the process is if a customer comes looking for an item that is in store