Poor customer service by FNB (I request for my refund)

I had a problem with FNB, I experienced cash flow problems n I made arrangements with them in terms of how I would make my repayment to my accounts with them and they agreed, I also made sure I made my repayment as agreed. And I stopped using the cheque account instead fnb continued to effect monthly charges on the account that was not active and made arrangements on it. I received payment from Sasol inzalo as part of my dividends after 9 years for an amount of R3,655.80 and FNB regarded the payment as if it was my repayment which was not. And I was desperately in need of that cash. I phoned them they I should write a letter confirming the purpose of the payment made in the cheque account, also proof of that payment form Sasol inzalo (computer share) proof of my shares certificate and my account details where they will refund the deduction they made as I pay them a specific amount on a monthly basis as agreed. So currently they are refusing to refund me R 3,206.80 as R400 remained in the account and I withdrew the money via e-wallet.

I humbly ask hello Peter to contact FNB and inform them to refund me my R3,206.80 as the money was not meant the monthly payment as I pay my monthly repayment.

Your assistance will be highly appreciated.

Kind regards

Makgolane, Mahlabe Lucas