Terrible Service received by Experian

After numerous attempts and emails I have bitterly disappointed by the lack of assistance received wrt the matter between myself and Experian. I have sent Experian my settlement letter received from Mandlethu Trading who incorrectly listed me on ITC in 2020 and till today I have not received any proper feedback and the listing is still reflecting on my credit profile as still owing and as well as missed payments. This is not true as I have never missed any payment with Mandlethu Trading nor have I got an outstanding bill with them. I have the letter to confirm this which has been sent to Experian to no avail.

Please can my matter be given urgent attention as this is now effecting me progressing with my life and planning.