Shoprite calling rotten thing

I bought inyala maize meal at Shoprite (Mount Ayliff) few days and only had to find out that it had webs and worms inside it, what's even worse I've cooked it twice my kids where complaining about having stomach ache and they dehydrated...it was not the first time buying the nyala maize meal the first one was the same as this one but luckily we saw it early and returned it, what if something happened to my me and my kids because of Shoprite carelessness