Shocking service from Discovery card

Had a credit card which was settled and closed in 2016 already, but after two years Discovery can't correct this on their system. Trying to explain this to Discovery only means that you get transferred from one department to the next, never have I experienced such terrible service. What makes it worst is that they handed this card over to legal and now one department is saying the card is cleared while the other is saying its handed over. Shocking service