Spoilt Purity Baby Cereal

I bought 6 boxes of Purity Baby Cereal Rice at Dischem Ghandi Square and found out a week later when i opened the 1st package that it was spoilt. The smell was very weird and the taste was worse. I fed my son thinking that perhaps it was how its supposed to be and to my suprise my son's poo turned blue. I stopped feeding him and i went to dischem to explain what i went through and they told me that they can't assist if i no longer have a receipt hence the lady who encouraged me to buy who works there and the other lady who was there when i bought them hold them that they remembered the day i bought them. I sent an email to them however it was never attended to. Im stuck with boxes dated due date of January 2022 however spoilt inside.