Failure to exchange n Bad attitude and service given by the manager

Went to a Mr Price Ferndale on Republic yesterday 17:44 bought a beanie for kiddies and winter tights(XL) the cashier was great n even advised that those winter tights if they don't fit I should bring them back as the cuts might be small but assured that an extra large would fit me as a size 38 lady and it's biggest size they have...this morning I tried them on but couldn't even go above my hips,had the receipt and tights properly packaged but when I went back to the store,the manager Olga said it's underwear n can't exchange...I don't know since when have tights became underwear🤷we buy jeans,tights,shorts that we not sure of the size n fit them at home n send them back but that's not a problem but exchanging winter tights it's an issue...That Olga lady gave me a nasty attitude,made me a fool n laughed at me with her security lady,sent me out n mentioned that I'm just wasting her time. I'm very much disappointed at the service she gave me cause it was unnecessary and uncalled for... I work in a retail store n the service given was unprofessional...