Not very customer centric business

I have recently paid large sums of money to settle my account. The money is ALL reflecting on the statement. HOWEVER Wesbank still levied me full interest despite the payments. When query this, I was asked to send them PROOF OF PAYMENT of these payments which was an array of direct transfers from FNB (Same banking group) and payment from someone else (also FNB). Despite all this - I must go into the First Rand Bank Group system (FNB) and send a Proof of Payment to THEM even though they can very well SEE on the statement that money was paid.

The call centre agent was not helpful and simply keep repeating to me that despite all this this is process and must be done before I get refunded.

My account still reflect an amount outstanding, despite me paying all amounts as per settlement letters received.

Really not very customer centric. They only care about their money - not the customer