Where is my paid up letter MTN?

MTN listed me on the credit bureaus without my knowledge even though I had paid the settlement amount based on a quote from them. I was told by the call centre that the legal department would rectify this at the credit bureau, but that the legal team do not provide paid up letters. It was their mistake AND they are a financial institution, which must be able to provide a paid up letter. In my opinion, it just seems like pure laziness to me (or incompetence). How does one fix this, other than going to the ombudsman?