Woolworths exchange

Bought a school skirt small size saw that it could not fit my sister, my mother sent me to exchange it at Woolworths ( canal walk / century city)and then when I got to customer services they said they couldn’t help me cause they could see it was already worn they can’t exchange it cause they can’t put it back to the floor . The cashier suggested I take it back to where it was bought and maybe they won’t see it .