Returning a product bought

On the 25th of november i bought a blk/opal pressed powder(makeup) at westgate mall. I asked if the powder has sponge inside and i was told it does not. So i had to buy the powder brush. The next day when i opened the powder it had the sponge, so i then think to myself but i dont need the brush. I hardly put on makeup, so dont even know how to use the brush, the sponge will be convenient. I then went to the maponya branch to return the brush, the person who assisted me didnt hear my full story, she said but you bought it at westgate. So im asking myself is that how people are treated, when i told her i cant go back to westgate. She then transferred me to the makeup counter. I didnt even go to that counter. So my question is if its a makeup brush do i need to go to the cosmetics department to return it or just go at credit/returns?