Shadrack ledwaba

I'm having a problem with MTN credit department for a paid letter, I was owing R11 126 so it's been 3 weeks since I made a payment. I need the paid up letter within 24 hours and my credit score to escalate since I'm debt free with them. MTN provides with poor customer service yet they call even after hours when they want their money, however when it's time for them to deliver they are sluggish and negligent to client.