So my experience is that Chorus do a really good job of following up with contractors when you call their support line and run them through the issue. I know others have different views on this, but my case involved lots of to-fro between Chorus and Downers, and often they would just put me on hold, call up the subcontractor, and then give me a live response.

Just my two (positive) cents...

The subcontractor can't do anything unless its covered by the original work order, and would still have to wait for approval of any change, so the primary contractor should work out some of these things before sending back to the subcontractor who comes back to do the job.