Carrefour Misleading Stock and Refund Trouble

I ordered cooking oil from the Carrefour website. Despite the package showing as delivered, it never arrived. When I called, they said there was an issue and promised to resend. Later, I received a message confirming my refund was accepted and the amount would be returned. When I called again, they said the product was out of stock and hence processed a refund. They insisted the website showed it in stock, but admitted it was an error and no stock was available. They accept orders online, but couldn't fulfill them from the store even though it showed in stock. They suggested ordering online again. When I mentioned the price difference, they said they couldn't do anything about it. It was a hassle to get them to not send the product. I used to shop there regularly, but now I regret it and don't recommend it.