Not sending paid up letter

Sometime in July 2022 I called cell c and requested a settlement amount. I was given one with payment details and reference to use. I paid on the 23rd of August and then called on the 27th of August to request for a paid up letter and the consultant said she'll log a case to wherever but till today I have not received anything. I've sent several emails and called them every second day since then but no one is able to resolve this matter. I need that paid up letter as in yesterday!!!!!