bad bad service

I have been struggling with receiving my settlement letter , they have been providing me with incorrect amount until i finally decided to just settle with whatever they last gave me of which was also incorrect because I have contacted mtn to ask the to tell me how much do i owe them , anyway I just wanted to get it over and done with , I was the promised a paid up letter in 21 days , Its been more that 21 days and i have been trying to communicate KEITUMETSE SENNE regarding this matter , but I have not received any response from her as the Resolutions agent , I then decided to call the call center , I spoke to Eunice Mabonga who informed me that a paid up letter request has not been sent to mtn as yet , now this was after the 21 days that I was promised my paid up letter only to find out that the request has not been done as yet . I have been sending the Resolutions department emails but I have not received not even a single response regarding my matter