Failure to close the account

I was a client of standard Bank for about 3 years, that I paid 200 random each month. Prior to leaving south Africa, I have closed my account with them, I paid all outstanding fees and closed it for good. Imagine my surprise, when two months after I recieved bills from them. They failed to close my account and charge me for it. I am living in different country now, I am trying to establish a contuct via email and phone, but am not successful. If I ever come to south Africa my credit record will be completely demeged.