My faulty National Geographic coat was not refunded

I recently purchased a National Geographic brand coat from Boyner stores, but unfortunately it turned out to be defective. On the second day of wearing it, the zipper opened when I sat down, and I noticed that the zipper got stuck when I tried to pull it over my chest. I took it back to Boyner, and they sent it to the company, but they rejected it. I find it ridiculous that they claim it was not a fabrication error. Boyner is just as responsible as National Geographic because we buy the coat from them. However, Boyner is indifferent and claims that the company is separate. In my opinion, the coat is not worth the money I paid for it, and I would not recommend it to anyone.