I was sold juice that has expired and over 15 days after expiry date.

On the 20th of November 2017 o bought groceries at Shoprite in our local mall in Jouberton in Klerksdorp. Only to realise when I got home that the juice is over 15 days after expiry date and this is after my whole family had a runny tummy. I've sent complaint to Shoprite and nothing has been said and done. Why do they have expired food on shelves in the first place? It expired on Nov 5 already. Someone is not taking their consumers serious and I need answers.