I settled my credit card with African in the beginning of August however was still debited an amount of R700 at the end of August

I settled my credit card with African in the beginning of August however was still debited an amount of R700 at the end of August. I called their call centre and was transferred to various departments with no assistance even after asking for the manager. I was advised that the reason I was charged interest R700 on a zero balance was due to me not closing my account after settling it even though I asked them close it when I made the payment. I have lodged a complaint on the Hello Peter website and have not received any feedback from them to date.