Dissatisfied customer

I Have never struggled to get assistance from a service provider just to close an account that was paid up more than a year ago. I have followed up almost every second month with a team leader in this organization Nkosentsha Nontsinyana <***> But there is no luck to get this account off my name. I have paid this account 4 Dec 2019. I have not received a paid up letter, I was promised that it will be sent in 21 days from payment but have received nothing. This still reflects on my credit score that I have an outstanding balance of +R5000 on my Edcon Jet account. This is absolutely unacceptable. I need this to be updated with the credit bureau.