Spoiled Yogurt

I am soo disgusted 🤮 and sick to my stomach about the product bought at Pick ‘n Pay which firstly had good quality issues which might have led to food poisoning, I bought -2 pack of parmalat yogurts and all of the right when you open them they have a brownish color which might seem as they are spoiled they are are far from being spoiled looking at the date and on top of it all I now fear that not being aware my had 1 for her snack and i only noted yesterday that they are not good to use. I am seeking a refund for this I can even attach all evidence