Samsung QLED TV Screen Issue and Customer Service Fiasco

Ever since I purchased my Samsung QLED TV, a white line kept appearing and disappearing on the screen. Upon contact, they diagnosed a faulty mainboard. Despite its recent purchase, I agreed to repair, but even after replacing the mainboard, the issue persisted. They decided for an exchange, only to tell me, "The product is out of stock, let's proceed with a refund." Initially, I requested the same product since the price had changed, but they refused. Instead, they keep prolonging the process, citing missing information. I trusted in their brand, but now I regret it profoundly. Even lesser-known brands manage to avoid customer distress by offering a higher-tier model if the intended one is unavailable, yet Samsung can't even refund our money promptly. Customer satisfaction? Non-existent.