Zara Sold Me a Defective Pillow Cover

I ordered four pillow covers from Zara, and one of them arrived with a noticeable defect – it's literally sewn together like a patchwork quilt. Although I missed the return window, when I contacted customer service for assistance, they agreed to accept the return but insisted I send back the defective cover. I expressed my willingness to return it if they could send a replacement, as sending the flawed cover back would disrupt the set. However, they claimed the item was out of stock, leaving me stuck with neither a replacement nor a refund. Essentially, I've been sold a flawed product for ₺650 without any resolution.