Fnb temp loan nightmare

I had a temporary loan with Fnb in 2022 which I defaulted on. The account was handed over and I've arrangements on the account which I've held up since 2023. Fnb has since listed the account on my credit profile 3 times. This has caused my credit rating and affordability to be negatively impacted as I now have the total arears amount x3 reflected on my profile . I've been in contact with Fnb via email and telephonically since February 2024 to have this resolved. They've confirmed in writing twice that it is an error on their side and it would be removed. I've lost count of the back and forth calls and correspondence which ends in promises that it would be resolved and I would be called to no avail. I'm am being negatively impacted by their error even though I've held up my side am continuing with my payments. The ball keeps being dropped only for me to start the process over . How can Fnb get this so wrong ...