In the first instance contact the lecturer or course coordinator for your unit to clarify. They can normally explain the grading structure to you or have any actual errors or mistakes corrected.
If you do not hear back from your lecturer in 5 to 10 working days contact education@cairnmillar.edu.au
If you are dissatisfied with the outcome of your request you can appeal within 5 working days from being notified of the outcome. See also SSP007 Student Grievance Policy and Procedure