Flagged on a paid up debt

Hi I was under debt review which i have fully paid it in 2018, now in 2025 im applying for a house it shows that im still flagged on it i tried contacting transunion with regards to this they ask me to tell debt review to send them clearance letter which they have done it numerous times i was even tagged on the email but im still flag and transunion is not able to assist me im this matter