My partner does the NBN backbone install into buildings with multiple occupants (aka MDUs). The stories I hear of bad planning by the NBN surveyor and misappropriated approvals by the strata manager where the OC/building owner were not involved is repeated regularly.
Knowing the shenanigans that come from the backbone install process check that your SM has followed the requested use of existing services. I also have a feeling that the existing Foxtel service can’t be used in HFC install, something to do with it being owned by Foxtel.
Otherwise I would add to JTs advice with: NBN responds well to noisy complaints.