Hi Guys, Ladies
Not sure if this a right place to ask this question, but I sure need some advice,
Basically, I bought an apartment from developer in mid 2017. fast forward to 2019. I notice that my balcony is leaking water. Every time heavy thunderstorm, rain water from my balcony will leak into the apartment unit directly below me.

I also notice several location, edge of my wall (concrete) where it meets with balcony sliding and windows become damp, I can actually see the water stain.

My question is, Is it possible to ask my developer to repair this defect ? if yes, where should I start ?
really appreciate your opinion, Thank You