Struggling for Settlement Letter

I am struggling to get a paid up/settlement letter from them. I settled the account in February 2023 and have called several times and was promised that i would receive it within 24hours. Its been 4 months now. My credit record has not been updated and this has negatively affected me. I called today, and after the agent listened , my call was dropped. Im at the point of making a complaint at the ombudsman.