Charged interest on a paid up Home Loan Account

Charged interest on a paid up Home Loan Account My home loan was settled and paid in full on 30 December 2024 and I had a credit of over R5000, and further requested for a cancellation. On 01 January 2025, Nedbank debited my home loan account and I then called to inquire and I was told it was for interest. What interest when there is nothing owing? It has been over a month and my query has still not been resolved nor have I received a refund but instead I'm given different explanations every single time and none of the explanations make sense.

My Home loan with Nedbank has since been cancelled yet this query still remains unresolved. I want my refund please.