You sound like you are really smart and coping the best that you can - just keep on keeping on and doing what you are doing - damage control.
I'm also sorry and frustrated for your DV not being taken seriously - the current system is so contradictory. There's no good advertising all over main stream media on being aware of DV, and how it won't be tolerated in society, blah blah blah if it then gets laughed off by officials in every quarter!
Above all, listen to your instincts about your ex and possible danger. Keep alert, watch what is going on around you, look for him in case he is stalking you, check the car before you get in - that kind of stuff - keep safe. Keep people around you if you can. You're doing the right thing not communicating with him unless through your legal representation.
And remember that we're here, and we understand the kind of stress you're going through (Centrelink makes everyone feel like crying!) - you're not alone
Whatever I have posted is my PERSONAL OPINION, not official single mother forum or legal advice. Just fellow-single-mummy ramblings - take it all with a bucket of salt!