BAD SERVICE

Freshstop Caltex - 18 Hereford street Groblersdal Sunday I asked my cousin to buy 2 packs of ice cubes from the shop, she did not hear me clearly so she bought 12 bags, we took the 10 bags back to the shop to return them as I did not need 12 bags. The lady at the till told us if we us if we wants to exchange we must speak to the person in charge and she went a called a white guy, he was not interested in want we said, he just told us NO RETURNS AND EXCHANGE at his store.so I want to know if that is allowed in terms of consumer act....