U Shape Waste Water Pipe Picha One Hole

[Nipponho 0]

Hi,

My kitchen has 2 waster water pipe. One U shape and another one straight down all the way.

My kitchen cabinet is supposed to be installed soon to conceal up these 2 pipes, so I had to clean and paint it. As I was cleaning, picha one hole. I can see droplets of water coming out (waste water from upstairs)

How come this type of metal pipe can picha. I called town council, they said they will not remedy it bec mine is resale, and ask me to find my own plumber. What should I do? He said that the hole can be patched, but I am worried that if I only patch, I am not sure if other parts will picha. And if picha and leak, kitchen cabinet will be gone case. Anyone knows how much does it cost to change the whole pipe? Will it exceed 1k? Spend money again 

[gladyslim 0]

check with HDB, not town council