You need to get yourself a lawyer ASAP to challenge the move.
Based on what you have said it does appear your ex may have been making noises as if she were willing to negotiate, but was really just stalling to give your child more time to settle in the new location. The longer your child has settled in the new location the harder it will be to get a court to order the child's return. Unfair as this may be, the courts first priority is the child's welfare, and once a child is settled in a new location the court will be less willing to upset the child further by ordering a return, even if other factors indicate the move should not be allowed.
Whilst your present delay may be excusable by the court given you were trying to negotiate, any further delay will only prejudice your prospects of having the child return and for this reason you should engage a family lawyer ASAP to explore your options.
Relocation issues aside, unless there is some reason you pose a danger to your child, the courts will support your entitlement to reasonable access to your child, so action is definitely warranted if access is being withheld, and the courts will certainly not look favourably on a parent who snatches a child in the way you describe.
If you need help locating a lawyer contact the Law Society in your state (the Law Institute in Victoria) as they can refer you to suitable lawyers in your area.
I trust the above assists.
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