Frustrating bank

In October of 2025, my spouse was contacted by 2 collections agents who Nedbank sold the the book to, offering a discounted settlement offer on his credit card. He gladly accepted and made the payment in November 2024. Since that payment has been made, we have struggling with Nedbank to get this off his credit report, even contacted their complaints department just to find out that the monies has been allocated to incorrect account and now when you ask them to allocate funds to the correct account or for any feedback, you get none.