Nedbank refuse to pay back money owed to me.

This is my second attempt to get Nedbank to act on my query. I overpaid a personal loan and they owe me money. This situation has been going on since 25 September 2024 with emails back and forth to every department in the building. Every department says it is another department's case. I emailed them all my proof of payments, THEIR statement missing my payments and did the reconciliation for them. The last mail to me was: "Send your bank statement and LAST proof of payment. Still no feedback. This has been going around in circles for over a month now.