Selling expired things and poor customer service

I bought few groceries at ShopRite this afternoon and when I got in car I quickly realized when I drank the product I bought that its expired. Quickly went to the shop and they refused to help me because it's 15:00 and they should be going home. They had the audacity to say I must come tomorrow as if they will pay my petrol for returning they expired products... They think they are making us a favour when they assist us as customers.