Errears for account that was paid four days before debit date

I paid my telkom account on the 20/12/2019 which I normally pay on the 25th of each month via eft now telkom debited my account on the 24/12/2019 that I no longer use so my account its in errears of R202.70 they are telling that my account was short R0.60 for that its in errears for that and old account didn't have money how is that because i paid four days before the payment date of the 25th very angry and unhappy customer