Shoes that N1city mall refuse to exchange

Today I got a bad experience from woolworths in N1city mall they refused to do a exchange for a shoe I bought in promenade mall on the 05 March 2022 the manger Mrs openshaw for n1 city says she can not take the shoes because it was already won but it was not won. And the shoes was a gift from sameone and the shoe was to big but the sizes for the person is 6 and I want a size 5 and that size 5 is in N1city mall