Paid-up letter

I was handed over to Shrives Incorporated by Foschini Retail Group. I paid off my account on the 27th of May 2024 and got a statement from them. the account has not been closed off on my report. I called Shrives Incorporated, and they said the account is closed on their side, but I will only get a paid-up letter after 90days. I called Foschini Group and sent them the statement that shows I have made full payments but i was told that they will only be able to remove or close my account once they get a paid-up letter. now how is that fair? a payment has been made but the account is still ruining my credit report because a paid-up letter has not been sent and Foschini group is refusing to close the account even with the statement sent to them. this is not a fair treatment and it's ruining my credit. I am very disappointed and angry at the same time. Kindly assist.