Put your sh!t in a bag n throw into their house at night
You were right the first time around to have confronted them was the best way possible to subdue any kind of noises you are bothered with in peaceful terms. To make some compromise is what you are trying to make, is what I get from your message, so be the first to take initiative and talk to them first. If they do not comply, then it is time for you to go to make report and exchange talks with the Housing Board regardless of what your circumstances are. I mean, you have a valid excuse, don't you? Explain to them with full honesty what your case is, what you have done in the meantime, and how you feel about it. Make short of it, and do not exaggerate in any manner to avoid creating conflict. Remember: these kinds of things should be dealt with as early as possible, or you're only digging your own grave as it escalates. It was nice of you to wait and hope the kid will stop after your own terms of throwing things, and knocking on your ceiling though.
Good luck!!
P.S. It was kind of unecessary for you to have mentioned they are "Indians" because it would only contemplate manners of racism on this post. And other people would feel welcomed to make such stereotypical nonsense. A noise can be made by any one of your neighbour regardless of their race. Just saying.
I have a similar type of problem. My blok located besdie an open space. Blok 528 Jurong west st 52. Everytime when fastivities like hungry ghost, CNY, hari raya, etc the Rc will organize loud parties there and even after I closed all doors and windows including those of my room, can still hear the noise. Cant understand why these things cant be done at the CC. Tonight itself there is a mid-autumn party going on. Disco music blaring. Ridiculous! Dumb RC trying to please some people but dont give a damn about the noise which is annoying the nearby residents.
There are really no laws to help us in regards to noise nuisances.
Many had tried with HDB, Police, Town council, MPs, CMC, etc.etc.
99% does not helps.
Anyway u can go facebook, see all those people there with what they had experienced.
https://www.facebook.com/SingaporeNoisyNeighbours
Talk to the parents.
just report, easy and done with!