Interest charges cannot be explained.

Earlier this week I contacted FNB to ask I was charged R128 interest of my credit card. I was promised a consultant will call me but instead I received an email:

"Kindly be advised that the interest you were charged was due us not receiving the full the statement balance of R659.64 on 25 August. A payment of R100 was received which was the minimum amount due as per your Debit Order instruction."

I was surprised to see the response saying I paid R100 whereas I payed R400. I rep**** and ask for the consultant to call me instead. After realizing that they were not going to call me I decided to call and ask a consultant how R128 interest was charged on R659 balance on 17.25% rate. Unfortunately, none of them was able to explain how this was calculated. All they do is transfer to the next consultant.

It now looks like no one knows how interests are calculated at FNB.