Bought house, minor repairs required. Builder wont reply. Looking for advice.

hey guys, i posted this on whirlpool too, but would love some advice from melbourne redditors. I just bought a new townhouse. There have been a couple of minor issues with it in the month ive lived here. including:

• Door knob to powder room doesn't unlock from internally, so you get locked inside.
• Builders have left goo dried on wall in powder room
• laundry doesnt have inlet for drain hose
• Rainwater pump installation appears to be covered in silicone and recently started leaking. (please see here

I just want to know if i can pursue the builder to fix these issues or do i have no means of recourse. Do i just have to suck it up and foot the bill? Would love some advice from you guys as to where to go from here.

EDIT: Just thought i'd add that this is a newly built house.