Absolutely disgusted

Hi i recently visited Clothing Junction Hillside Mall store to return a dress which was given to me as a gift, when i put the dress on i noticed that along the seams of the dress there was an opening as if it wasn't stitched properly, i went to the store to exchange it for the same dress, i explained to the guy the issue and that it was a gifted that i didn't have the tag for but the person who bought it had a picture of the transaction which i provided, the guy who assisted me was extremely rude, he began to shout at me that i had made a hole in the dress and i must just go because he will not change the dress, i then explained that it was a gift but he still wouldn't budge, i went to call my elder sister to help me explain but when we entered the store and she approached him he ignored her and walked away, she then followed him and said excuse me im talking to you, he continued changing the mannequin saying he is busy, she then told him that she needed to speak to him and ask him why did he handle the situation in that manner, he started to shout at her and told her that she's "****ing with him" my sister then became very upset and asked for his name he refused but she then tried to ask the other employee and she refused to give his name, she then asked for the manager and they refused to call them, eventually my sister was fed up and decided to take a picture of the guy (which we have) he then tried to grab her cellphone out of her hand whilst blocking his face, overall im not even worried about the dress but the way we were treated was unacceptable coming from a reputable store, i am disgusted beyond words and will be taking this to all social platforms to expose this ********* behaviour since i have contacted you and I've got no reply at all.