If you are changing your mind then they may not refund. This is the excerpt from the site
"Refund of the Visa Application Charge
Mandatory refund
You may request a refund of the visa application charge, however there are very limited circumstances where the visa application charge must be refunded. These include the following:
your application was 'unnecessary' at the time it was made
your application is made because of a mistake made by the department
the applicant dies before a decision is made.
A mandatory refund is not available if you change your mind about continuing your visa application after it has been made. The visa application must have been unnecessary at the time it was made. The visa application will not be considered unnecessary if, for example, you no longer need a visa because you no longer want to migrate to Australia.
Discretionary refund
The visa application charge may be refunded, if the visa application is made because of a mistake by the applicant, for example the visa applicant mistakenly applies for the wrong type of visa. The application must clearly have been mistakenly made. The migration delegate has absolute discretion to make a discretionary refund.
A refund will not be given in situations where you subsequently decide that the visa application was a 'mistake' because, for example you:
change your mind about continuing the application
do not satisfy a criterion for visa grant
claim it was a mistake to have applied because your visa application was unsuccessful (that is, you state that you would never have applied for this visa had you known your application would not be successful)
consider in retrospect that you applied for the wrong class of visa.
You can make a written request for a refund stating the reasons why you consider your application fee should be refunded when sending your withdrawal letter to the office processing your visa application."