Truleconcerned,
the information you have provided applies before a fence is replaced.
if you read further on the website, the notice to fence can’t be retrospective.
Whilst the dividing fences act is the governing law, it will require a visit to the courts to sort this out as the othe strata has already declined to chip in.
This is an unusual situation and could be easily solved if the other strata had agreed to chip in.