Charges on "closed" account!

On the 30 July at 13:19pm I called MrP money to close my account. It was confirmed that I had no outstanding balance and that it would take 24hours to close my account- this should've been resolved by the 31 July!

I have now received an Aug statement reflecting a R17,00 balance. Why was my account not been closed as instructed!? I refuse to pay this amount as the balance reflecting is due to incompetence and terribly poor service!