PAID UP LETTER!!!!!

I am having the worst service from Cell C. Cell C is unable to send me a Paid Up letter. Cell is causing me a huge inconvenience. This is delaying my application for Vehicle Finance. I contacted Cell C the 8th February 2019 and I requested that I receive the paid up letter urgently I spoke to a Lady by the Name of Dudu Ndlozi who is a Team leader in the written consent department she couldn't get this done for me. I also spoke to Slindile Shezi she also could not assist. This morning I get a call from M Seabi who said she is drafting me the letter and will email me shortly this was around 9am and the email never came then I contacted Cell C numerous times to get someone to assist me eventualLy I got a lady who provided me with an email address of the lady who promised to send me the letter. I sent her an email she has not responded and I am still without this paid up letter. What on earth must I do just to get a paid letter for an account that I closed in 2017 already. I am frustrated because this account with Cell C still reflects on my ITC and is affecting my current credit application. I am beyond frustrated all I was is a PAID UP LETTER!!!!!!