settelment of Loan account

FNB Loan Department, I have a loan account for the past few years and eventually reach the end of the term. However due to my account that was not debited last month I have proceeded to make payment on the 25th of February I made the payment that showed outstanding on the FNB app. R2189.14 thinking that it is now settled. On Monday the 28th of Feb my account was debited with the amount of R2548.98 I phoned FNB and FNB loan department both parties explained that they are unable to do a reversal as it will only be possible after 24 hours fnb loan department requested that phoned back on Tuesday to request a refund. I have accepted this however the guy from the loan department. Keep on telling me that what I should have done. (You shouldn’t have made the payment in the fist time, the payment that you have made were the opening balance not the settlement amount…….) On the fist of March I phoned FNB to reverse the R2548.98 debit order and made a payment of R359.84 to reach the settlement amount. However last night FNB loan department have transfer the amount of R2869.73 in to my bank account. This bringing the loan account again in the Minus -R2548.00 (Not settled) I did not request a refund (this normally take up to 7 days) Phoning them again this morning to get this sorted out. The same guy again told me you should not have reverse the payment you should not have done this or that. I asked him to send me a settlement letter but he keep on bugging me with what I should have done or not done. Then being mad I asked him to put me through to an manager ending up back at him. Eventually this were not sorted out still did not receive my settlement letter. Is this the way making money works for FNB. I paid the account paid more than the amount in rent and taxes over the years but still you find a shady way not to settle this account. Please contact me they guy with the brains and not the arrogant one.