I Request for Carrefour to Procure My Lost Items, Not My Job!!!

The item I bought from the Carrefour seller on Trendyol is now lost in transit, a shame. MNG Kargo tells me they can't find the item and refers to the seller, but Carrefour says I need to talk to the courier directly about the problem, why is it me dealing with the problem...anyway, I am not able to obtain the item... for which I have already paid. Even though I've tried, Trendyol doesn't respond and doesn't step in to help the seller, which makes me very angry. I've been trying to get back the things I bought for 11 days, and even though I was told there would be a solution, nothing has happened. It's very worrying that customers aren't happy or getting help. urgently need my order, this situation to be fixed right away.