Turkish Airlines Customer Service Led to Missed Flight

I utilized the miles I had accumulated in my Miles & Miles account to acquire a plane ticket for my sibling. After realizing that I had entered the wrong passenger name, I promptly reached out to Turkish Airlines to correct the mistake. Regrettably, due to misinformation and a failure to follow up, my sibling was denied boarding. I am frustrated with the lack of responsiveness and indifference displayed by the customer representatives and airport team at Turkish Airlines. I kindly request a prompt resolution to this matter. The approach to customer service is not solution-oriented.