Not providing paid up letter

On the 8th November 2017 I settled an account with Nedbank which was in debt review. I immediately notified them by calling and sending an emial stating that i settled the account with them and send a request for paid up letter. Through calling they explained that they have to cancel the account first before sending a paid up letter and that will take 3 to 5 working days. It's the 13th day without a paid up letter since I settled on th 8th Nov 2017, I've been calling and sending email but they don't provide what they should provide which is send me a paid up letter, simple. Every time I call they tell me about 3 to 5 working days but it day 13 now.