JDG Hi Finance dont close account after you settle

In 2013 I bought on credit at incredible connection, I settled my account 29/01/2014 and had no problems since then till today when I received my credit report and to my surprise there it shows that I still owe JDG Hi Finance money. I tried to phone and sort this out but it seems like no one is willing to help me, I want them to close that account like they were suppose to do when I settled the account back in 2014 now this affects my credit score