Structural defects and poor workmanship

I bought a property from Kaan Development in 2022 and I moved in on the 25th of February 2023, I have been complaining about the structural defects since then and nothing was done about it, Kaan is pointing a finger to the contractor whereas I didn't buy from the contractor. I had a meeting with the owner of the Company, and he stood in front me telling me I can go report to NHBRC, he said he can't fix anything because I have been leaving inside the house for over 18 months. I'm very disappointed about this Kaan development. I regret everything about this property, roof leaking, bathroom taps are skew and not aligned, the baths are not correctly fitted, the ceiling is black showing water marks, I can see outside even if the doors are closed.