The charges depend on how you are applying (as a migrant worker, sponsored spouse etc)
See the link below, generally all charges are refundable besides the fee for the application itself, the second link lists other charges apart from the main visa fee. Charges are refundable if the application is invalid (incomplete) but there is no mention of a refund if they reject it for a valid reason. I would suggest getting an immigraiton lawyer.
Visa Charges Forms & Booklets