Black listing paying customers

I recently discovered that the above-mentioned company put me on a credit bureau, for missing one payment which I have paid.

I was told to email the delisting department which I did and I was told that the turn around time is 24hrs, it is 12days later and still nothing. I needed to get a loan from the bank that's when I was told all this and given two different reference numbers, still nothing. Did I write an unsatisfied email yes because nothing has been done and my things are standing.

What is one to do to get this Clarence letter, please tell me!!!!!!!!!