Large debit order occur randomly

This has happened 3 times too many, I had Standard bank set a debit order for the amount owed on my credit card, lets say R4000 is owed, normal debit orders occurring with that amount in mind will process +/- R800, however every 4 or 5 months almost the whole amount if not ALL of it is debited in ONE payment.<br> <br> Unless I make a payment to pay the card off in ONE go I find this unacceptable, If this is how Standard bank likes to operate then I will happily move to FNB.<br> <br> Thank you.