ZERO effort to get resolution, Managers are useless

I've had just about 2 and a half years of issues trying to get my Credit Card Account (through Nedbank) closed. In 2016 I could not afford the card payments and made special arrangements. Part of the arrangement was that I would have no further use of the card (which is to be expected) and as soon as the full amount was settled the account will be closed and new application would be required if I wanted a credit card again. I agreed to these terms. On the 3rd of November 2016 I requested a settlement amount and confirmed that the account will be closed once settled. The amount was R14943.81. I settled that amount on the same day. I used the telephonic banking service at Nedbank (Bellville the bridge branch which is now closed down) to phone the card division to confirm that I've made payment. They've acknowledged receipt of the money and again verbally confirmed that they'll process the closure of the account. To date this account has NOT been closed and I'm being harassed DAILY for payment on some amount that's in arrears. I've spoken to several People (Sharissa 04/04/2018, Sharissa 11/04/2018, Lekoba 16/04/2018 and Thabo 17/04/2018) and explained the issue. Sharissa said she'll take it up with her Manager (Sandy) which is now on leave and I'm yet to hear from her. Thabo's manager Jabutwana was supposed to phone me yesterday (18/04/2018) with an answer. I'm still waiting. Please can I get a resolve ASAP on this? Thank you