Debit order taken off on paid up account

My loan was settled in full on the 24th December 2015 via debit order, however on the 29th December 2015, you still took the premium of R1335.10 off my account? How does this happen? Surely an early settlement debit order should over right any additional debit orders?<br> <br> Please rectify and refund the debit order ASAP.<br> <br> I await your urgent response.