I NEED MY PAID UP LETTER PLEASE PLEASE

I really don't understand how this company works. I settle my account on the 20 Dec 2019, until today I am still waiting for my paid up letter. I send them several emails and phone calls , no one seem to care but when they want money they call every day.

This is my last attempt , now I am going to take you straight to ombudsman. All I need is my paid up letter , I will remove my name from credit bureau as it seems as if it will take you decades to do that.