PAID UP LETTERS

The service is very poor. I've been trying to get my paid up letters for the last five months, sending emails numerous times before they can even respond to you. When you call them you are being sent from one person to another, this is really frustrating and annoying. This is affecting my credit score. Can I get this sorted. I even asked if I had debt still outstanding, the answer was no. Why is so difficult to get paid letters 😡?