Settlement letter for Standard bank credit card

I have been calling MBD and asking for a settlement letter ever since I paid the balance but I still have not received it until now. They always say that I will get it within 48 hours but I ran out of count of 48 hours that has passed. They are quick to call for an outstanding amount but when it's time to provide a settlement letter why is it taking forever. I use my airtime everytime when I call them. What are they not sending it, it is so frustrating. The outstanding amount for Standard bank is still reflecting on my credit score.