I have been trying to cancel my fnb credit card since the 10th of August

I have been trying to cancel my fnb credit card since the 10th of August. I have paid the settlement amount within the agreed period, completed their cancelation form and sent it on the 10th. To date, I have not had any response from fnb. Not even an automated one. I have been calling them with my own airtime, not receiving any assistance or any clear indication as to when it will be canceled. FNB always only responds to me when I make public complaints. The service is absolutely terrible.