Bought goods and didn't receive it

I purchased a few items from Shoprite, when I got home one of the items wasn't packed in my bag. So I contacted them and explain that the product was maybe put in another customers bag that was in front of me in the queue. They say its my own loss they are not going to replace the item. I don't feel that it's fair, because it was their packer that put my item in somebody else's bag... They now say they will take action against the employees involved... What about my loss???