Standard bank credit card ***********

I have a credit card with standard which was handed over to debt collectors...i was given a settlement amount by the debt collectors which i paid ..i was also given a paid up letter which i have.. every month i get statements from standard bank saying i owe the credit card i have called also and they asked i email the paid up letter which i did..Today again im getting a statement and the balance is just increasing.... So i would like standardbank to let me know when this account be closed as i have paid everything and i have the paid up letter from the debt collectors....this is going on from September..and im really tired now