Refusal of refund for expired food

I bought coke and lekker gain sweets, both were expired... They manager Zilungile refused to return the coke and told me I have drunk the coke and it had expired this month so it is still fine.. She kept making remarks when I wanted to do an exchange that I know they are expired yet I ate them... Both the coke and sweets are still in the shelves and it seemed like there was no intention of removing them. One cashier also said a customer complient about their products too