HDFC Bank — Credit card settlement

I have taken the settlement on November 2020 and it has been approved for 44700 In 6 shots. I have paid all the proposed amount within the maturity date i.e, paid all my dues in March 2021. An officer from HDFC bank called me and threatened me that I have 3000 pending and if I am not paying they will send some goons to home. I had paid the pending 3000 in the same day and the manager from hdfc bank said me that he will issue the NOC within 15days and I have every proofs like challans and call recordings with the hdfc officers. Still now I didn't received the NOC and if I call the customer care they are saying that still 30k is pending on my card. Due to this issue I'm unable to close my jewel loan in hdfc. For paid amount still I'm facing the issue. Kindly do the needful. I'm mentally suffering a lot due to this. I need the NOC to be isssued from the bank side or else...