So what happened 2 weeks ago to trigger such a complete change in ex's behaviour ?
Assuming you weren't the cause ( realistically) of creating her mindset that she simply just had no other option than to ring the cops to sort you out, then you need to honestly assess the TRUE situation & determine just how mentally unstable & willing to use your kids as pawns to control you & hurt you & potentially severely limit or even remove you from further involvement in their upbringing. You need to learn present day family law & all it's disgusting filthy aspects. Research the immoral, corrupt, bias system & the disgusting, child abusing tactics encouraged by greedy money hungry agents under the guise of " having best interests of children " as their driving force.
Of course if you were a tool 2 weeks ago & assaulted, threatened your ex and/or the kids, or you got smashed & abused/harassed her, or threatened to.....that's entirely different.You need to own up to it & seek help in fixing up the problem.
Only you can be 100% open & honest with yourself regarding what triggered such drastic overkill reaction from ex & whether or not your kids genuinely will be worse off through life if they had no relationship with you.
Cold reality is though, brother, that regardless, you are in S.A ( direct connection to potential Intervention orders sought ) & you are male ( same ). That puts you 2 laps behind the start/finish line to begin with! Wrong? Damn right!
But hey, there's an "epidemic" of family violence occurring in Australia presently & by some magical coincidence it is strictly male perp.-female victims
Good luck.........you & the kids are going to need it.
That is today's reality!