Credit Account still not closed

In December 2014 I went to ABSA Clearwater to close my Credit Card that I haven't used in years. I received a form stating the account has been closed. In January I received a statement and assumed it was sent before the account was closed and ifnored it. February came and I received another statement. I called and complained and the lady on the phone assured me that after my call my account is officially closed. Apparently not, I received yet another statement this month! I am so fed up with ABSA, I stopped using them 8 years ago because of bad service and high bank costs, but I just can't get rid of them!!! Throughout this I still get sales calls for another credit card ! WTH? Can someone please sort this out and stop trying to sell me stuff?! This is the worst bank ever...