Farmacy...richards bay boardwalk

My wife sent me to buy menthol crystals from Checkers Boardwalk Richards Bay. It was R189 but i bought it not realizing my wife only wanted it if it was much cheaper. So when i returned home she asked that i return the item. But the pharmacist refused to refund the item although it was still sealed and with the slip. I honestly made a mistake by buying this item and they should have allowed me to return it due to it being sealed.