Expired drink

I bought Zip cool drink on Monday 10 August public holiday, the following day after I had already given it to my child to drink I noticed that the test was off. At first I thought it wasn't cold enough since I didn't put it in the fridge only to find out it had expired in March. I am very disappointed with Shoprite especially that one because this is not the first time I'm getting expired goods from them. That could have made my child sick because she drank it without noticing it didn't taste right. What I fail to understand is why something that expired in March would still be on the fridge.