Who pays for building defects?

Hi, to cut a very long story short. Our Body corporate has already forked out close to $3000 to get to the bottom of a water leak in our balcony. This money has paid for the original diagnostic builder, the removal of the ceiling to do a water test and an engineer to come and inspect if it is possible to re attach a motorised awning that has contributed to the leak. I'm being made to feel guilty for spending this money which is not one individuals, but rather 'OURS'. (This is one problem..)

During the water test it was found that a secondary leak is also contributing to the problem coming from upstairs on the balcony under the door frames. The original tiler has cut the aluminium flashing and water has been slowly getting in from day 1. The builder is claiming responsibility for that. Secondly, the engineer has also stated that the balustrade has not been attached properly and would in time have affected the leak that the awning has sped up between the facia trimmer and the tiles at the front of the balcony. The builder for 9 moinths has been saying it's the awning's fault and they should pay however, I believe this is also a builders issue. It is also a safety issue now too as the balustrade is attached by screws through the fibre cement panel and into the LVL which the builder states is not structural(the LVL) but in fact it would need to be if the balustrade is fixed to it. Our body corporate is holding out on us to commence repairs until we get our money from those seemingly responsible and my question to you is, shouldn't they be acting with our sinking fund to make good of this rather urgent situation and then fight for the money later? What is the law? I want to deal in facts not opinions anymore!!  Thanks for your help!