My ex has been lying about her income since last years assessment, telling child support her income is 12K and she is casual, when for 80% of the year she has been part time employee earning 45K and in the last 3 months went full time now earning 55K. I’d be lying if I said it didn’t annoy me, are there any grounds for back pay or do I just have to grit my teeth and deal with it? She refuses to let me have more time with the kids stating that she “cannot afford to lose more child support money” then to find this out does not make me happy.