Bad Attitude towards me upon enquiring from Ezmulene, a cashier at the store

I visited the store to buy a gift card container/envelope, today after 5pm. As I approached Ezmulene and explained to her what I was looking for, I noticed she was getting rather agitated by my enquiry and certainly her body language wasn't reflecting willingness to assist cordially. She subsequently, cheekily, said, with some sarcasm in her voice, "I know what a gift card holder is" almost dismissively. So we went along toward the tills for her to show me the rest of the products, by which time other cashiers (and customers) were noticing her being agitated. That is when I decided I will not tolerate this behaviour and requested to see the manager but I was told by another lady to whom I was referred to to ask for the manager that the manager was not available. I must say that the lady I was referred to didn't at all demonstrate an attitude to resolve this, instead she kind of quizzed me, as though she was covering up for Ezmulene. I'm quite known at the store by a few cashiers including the security lady. I go there quite often mainly to buy magazines (Financial mail, Finweek, Forbes, Fortune) and an occasional book. I will not go into a store just to make someone's afternoon bad. But what I will not tolerate is bad attitude when I am simply enquiring. How difficult is it to simply show a customer what they want? Not on! And definitely not acceptable !