Disappointed by Kaan development -Leaking roof on a.new home

I app**** for homeloan in 2018 bond approved the same year.The structure was build in 2019 and completed in 2021. I moved into the new home on the 27 September 2021. During the week 6-10 February 2023 it heavily rained and I experienced a roof leak that water drained though the wardrobe into the bedroom. On the 11th February 2023 I called Kaan office with a query that there is a roof leak and would require their urgent assistance.The admin lady informed that nothing can be done as the hand over was done though we agreed that must send an email on Monday. On the Monday 13 February 2023 I send the email in the morning as advised.I further found someone to.check.over the roof and he indicated that there is a Structural defect. Later I then followed up the mail with a call of which I struggled to get the relevant person to assist and was later connected to someone who promised to arrange someone.After 30min of no contact I check to find the Project manager's (Mark) contacts in Homeowners group and tried to explain the equity directly. I regret the decision as he became too rude and told me that Kaan has nothing to do with this as the home is four(4) years old. I disagreed with and asked what the NHBRC stipulates.I suggested come and investigate then we agree on what needs to be done. He said then I can go to NHBRC if I want and bluntly dropped the line. To date Kaan development have not responded to my email and never returned a call with the person to assist.