Still Waiting for My Paid- Up Letter after Early Contract Cancellation- Vodacom Poor service

I have been requesting a paid up letter from Vodacom since last week with no success. I did an early contract cancellation, paid everything in full and submitted all the requested documents. Every time I contact customer service, they keep telling me different stories saying I will receive the letter within an hour, then changes to within 24 hours, and then after 3 days. Yet, I still haven't received anything. This is frustrating and time consuming to say the least. All I need is a simple paid up letter for my account I***7.