Telkom paid letter

I had a contract with telkom which i was in areas. Then made payments arrengement with them. After i paid on the 21 of December 2020 i asked for a paid up letter that i have been promised that it will issued after seven working days excluding the December holiday. Then i called again after seven working days the call center consultant said its after ten working days. I then called again another call center agent said it will be issued after twenty working days. They are all not willing to escalate my querie to their supervisors. Im really frustrated