Bad customer service.

I bought shoes at Rage Alex mall to wear on my granny's funeral and i bought a size 5 because it was small cut but when i got home, i wore those shoes and they were big, then i went back yesterday 17.08.2022 to exchange for a smaller size but this 1 lady whom i assume she's the manager there refused to change them for me saying i wore the shoes, they have scraches and she can't sell them to anyone, fine i get that whole thing but the shoes are new and in good condition to be sold again..so i want to know what must i do with a size 5 when i wear a size 4 and y was she giving me that attitude she gave me, i paid R275 for that pair of shoes, i did not say i want a refund but an exchange, i felt so small and humiliated for asking what's mine. Rage Alex mall dissapointed me so much because at times you will find old shoes in their shelfs and not ask anything but for them to refuse to exchange the shoes for me is uncalled for. i am not happy with the service i got and still want to exchange them for a smaller size. please advice on going foward .