Shoprite eyethu mall. Broken bokomo weetbix

Thursday my min bought 900g weetbix at Shoprite eyethu mall and i opened the box Friday late to pack few for the following morning for breakfast only to fund that all of the weetbix are broken inside, tried returning them yesterday we were told that it's not their fault and we should have returned before 3 days.... Poor customer and Management service.... now I'm stucked with broken weetbix i cant even eat them as they have a funny smell of old plastic...