Family Tax

I was getting family Tax for my 4 children. Centrelink / Child support decided that I did not care for my 4 children during the separation until divorce. I was never told how the decision came about because my ex-husband confirmed that I had care and did not claim any family tax. I was told I needed a third party full of age to confirm with the court that my kids were with me every night during that time. Well, as a single mum there was no other adult in my household to confirm that. My anxiety was beyond the scale when my appeal generated an automated approval of the previous decision. I was ought to pay $1000 back per week (on a low income) or legal concequences were put in place. I got a loan to settle the matter. To this date I wonder, who actually cared for my kids if apparently it was neither mum nor dad???