Lufian Refuses to Refund My Sweatshirt With Elastic Defect

I purchased a sweatshirt from Lufian.com in November 2024 for ₺700, and from the very first time I wore it, there was a loosening issue with the elastic on the lower hem. I used the product only 4–5 times in total, but the problem persisted. After June 15, I returned the item to Lufian customer service for a refund. The defect was acknowledged, yet for about three months I received no updates. When I went back to the store, I was told that the faulty product was out of stock, a refund could not be issued, and if I wanted a new one, I would have to pay nearly three times the original price. It is unacceptable to admit the fault but not resolve my grievance. Despite the product being under warranty, neither an exchange nor a refund is being provided. I am demanding a refund of my money and expect this issue to be resolved immediately.