Bad mannered rude till personnel

11 March 2020 I went to truworths East Rand mall, and purchased two tops, I came back around an hour or two later, the security guard noticed I had been there shortly before so he approached nicely and I explained I needed to exchange for a larger size, he kindly request to see my slip then directed me to the tills. I get to the tills ND the lady there has a nasty attitude, she looks me at funny ND asks wen did I buy this top ND it has stains. I tell her to look the slip as the date ND time of purchase is there but she keeps insisting abt stains, I tell her it's about an hour since my return, i myself didn't check for stains, she tells the lady who was assisting me in the 1purchase to check items in future,I tell her why wud I check, I'm expecting that the item is new and clean ND all relevant tags were still on the dark Navy blue top. She still gives me a funny look, Continues to talk abt stains I nor the lady who helped me 1st cud see, goes to back,comes back ND only then decides to do my exchange. She acted like I did something wrong or she was doing me a favour. If I wasn't in a hurry I wud have asked to see her manager to address what her problem was exactly, I still needed to buy more items in the women section but the girl put me off so much I decided to leave to another store