Roof Plumbing Complaint

Hi everyone,
I just have a couple questions about roof plumbing, I recently had my roof fixed by Local Melbourne Roof Plumbers they quoted 10k for fixing the roof and 7 years warranty. However, after fixing, the issues still remain since we can visibly see the droplets/wetness on the wall of the room during the rain. The communication from the company was great up until they went bankrupt recently and they failed to honour their warranty. So far I have paid 4k and I have stopped the direct debit with 6k remaining until I can get the answer.
My question is who should I contact (VCAT or VBA)? And what is my right in this situation? The property is a townhouse and I contacted body corp initially when we noticed the leak and they said roof is not in cover even though it is a part of structural building the body corp manager mentioned that roof fix is considered maintenance and I need to pay out of my pocket for that, Is it true?

Contact VBA plumbing division and ask how to make plumbing complaint

The work should be insured and you may be able to recover much if not all of the money fairly easily. Some general information here: www.metropolis.melbourne

In my experience roof is essential element of the building envelope and hence a common property and should be covered by owners corporation however a detailed review of all documentation is essential, maybe they are blowing you off.