Large Debit Order after arrangements made!

I have made a arrangment with Personal Loans and spoke to Zanele on the 15/09/2020 at 09:57 stating my current situation and he set up a amount agreement of R500 to be paid on 27/09,This morning i have a notification on my banking app that Nedbank is trying to debit me R2.416.02 and due to the insufficient funds in my account i am now been charged bank fees for this,I called this morning and spoke to Zanele again with less airtime she made me hold on for along time and she says the arrangement is in place so i asked he why is this large amount been taken and she does not know? The call was cut due to my aitime been finished and she never had the decency to call me back till now 12:03. I want this to stop really coz i have arrangment and i cannot be calling all the time and posting here due to this mistakes by Nedbank!! Some one needs to put a hold on this debits if there is a arrangment! i expect feedback URGENTLY!!!!