Why hand over my account to Collections whereas I pay you more than monthly bond repayment amount? It does not make sense!!

I have a home loan with Nedbank and I am up to date with the payments as they go off from my payslip. I got a shock of my life today 23 June 2025 at 16h17 when I received an SMS notification saying "We have not received your payment as per our most recent arrangement for your home loan. You can resolve this matter urgently by calling ***". I attempted to call this number however it was closed. I then called ***and a lady who answered the phone confirmed that my account has been sent for collection. I need to know what is all this? I have never made any payment arrangements as I have never had any payment issues??!!