If you don't agree with a CSA decision
If you do not agree with a decision made by the Child Support Agency (CSA), you may have the right to have the decision reconsidered.
If you live in Australia or a non-reciprocating jurisdiction you must object within 28 days of receiving the CSA’s decision.
If you are resident of a reciprocating jurisdiction you must object within 90 days of receiving the CSA’s decision.