Got problems with CSS Solution and Cell.C mobile they never cleared off my name on credit score after debit settlement

Got a call from the above mentioned account last year to tell me they were sent by Cell .C mobile to collect the outstanding balance. Ok since I accepted "the" balance because it's frustrating to give all your banking details to a company for debit orders and all of a sudden you are behind by 3-5 of not paying. When you ask how possible is that it's a story after a story. So the CSS Solutions and myself settled the balance and got the paid up letter but what surprised me today 14/02/2023 to find out am blacklisted my credit score never cleared off. About to 4 months after settlement I very disappointed