Very disappointed

I would like to express my disappointment to Dis-chem Giyani(Masingita Mall) on the 23rd of December (Monday) I bought milk (cartons) for my baby and only to find out the whole pack has expired… and, only noticed cause i wanted to make cereal for him and asking myself had i not discovered that and just poured for him to drink what would have happened? I’m still shocked and want my money back cause this is a very serious matter and you are not allowed to sell after expired date. I need this to be solved PRONTO!