Just give me a settlement letter!

So I requested a settlement amount that I needed to pay. I paid the settlement amount before the 7 working days and asked for a settlement letter. I receive a statement showing an amount owing and then I ask them why? I call no one answers Now it shows on my credit rating that I haven't paid an oustanding amount, but before they use to deduct. After I paid the settlement amount no more debit order takes place, but credit report shows that I owe. Why can you not automatically send out a settlement letter, what is so difficult about this! I have been a customer on your other products for a atleast 10 years. This is **** and I pray that I won't get this service when I retire.