Account closure when your banking with discovery bank

I have open an account which was linked to credit card and they never explained that I will pay interest without using it and after I decided to close it and pay all necessary cost but it’s been 2 years without closing it and they always promised me to close it but it never happened because of error happened on their side while closing because never stop to add interest monthly that I need to pay and I’ve told them it will ruin my credit score but they always fooling me that they will call after everything it’s done but it’s been 2 years my latest reference no is ***8 it’s very difficult to get to the bottom of the problem and close the matter because you will get them on call only and it seems like they have *********** staff because they can’t resolve a small matter of closing an account go 2 years and ruin my credit record I won’t advise anyone to bank with them with this poor service I’ve experienced