Fairmont homes NSW built 2015 very poorly

I would give the builder a ZERO as we been dealing with the ceilings in my home being cracked and caved it from the storm on 9th feb 20. Out of 5 of the 6 houses built by Fairmont homes (on the same block Byrock Pl, Hinchinbrook) had the same problem with the storm on that Sunday, and we been contacting both Daniel and Tom (the directors of Fairmont homes) avoiding the reply to our problems. My home was built in 2015 and it should withstand the heavy rain water and the ceiling was caving in the garage. It was a newly built house from a turnkey home & land package. All the houses built on this block of land was bought brand new as well. Early on 2016, I experienced a problem with the rangehood where they did not build the ventilation outside of the property and the main door was being dragged onto the tiles as we use it. It took over 4 weeks for them to send someone out to fix the 2 problems. Now the directors are saying that they have the fair trading on their side and that the building warranty is for 24 months when it is built, but we have a major structural defect that covers for up to 6 years. They have been sending out letters and emails backing themselves up using statistics that the weather affected the damaged ceilings, instead of owning up that they are using poor building materials and poor construction work. Tom did told us that he would get someone to patch the damaged ceiling 2 weeks ago and he never did by avoiding the phone calls. Many of the neighbours that we know had experienced this same issues where the builders are avoiding to help us and rectifying this problem since 9/2/20. We now have to folk our own money to get a tradie to fix the damaged ceiling asap. My neighbours and I are going to seek justice from this slack builder.