Agreements, changes and unpaid child support
You don't have to accept the formula, but the paperwork has to be right.
Parents can agree on child support between themselves. A child support agreement can be limited or binding, and a binding agreement needs both parents to get independent legal advice before signing. If the formula doesn't reflect your situation, for example because of high costs for a child's care or schooling, you can apply to change the assessment. If payments stop, Services Australia can collect child support for you.