Credit Card debt not canceled after I paid full

I am very upset with Nedbank. Last year October I fully paid my outstanding credit card balance, I then sent t the proof of payment to Nonkululeko Sithole via email and she rep**** saying "thank you we received the proof of payment and we will attach it to your profile" But I am constantly receiving debt collection calls threatening to to take me to court and this is really starting to cause a rift in my life and finances. I keep telling the agents I paid and I no longer owe them anything even decided to close the credit card. Nedbank should give me answers please 😡