Double debit on my account

I don't really understand the debit order system. My agreement with Nedbank was for them to debit last day of the month. Which they fial dismally on doing that. Last debit went off on the 28 Feb. To my surprise yesterday(15-03-2024) afternoon I receive a notification that my account is in arrears. I just ignored it coz I know that my account is up to date.

Well this morning they debited my account. How crazy is that? And I can't even reverse it.