Who pays for damage from sewage backflow?

Message:
I would greatly appreciate your advice.
I have an apartment on the lowest level of apartments in a large
apartment block in Sydney CBD. Recently whilst I was away there
was a blockage in the common property sewage pipe which caused sewage
to backflow through my laundry drain through the hall and entrance and
onto common property outside my door.

The sewage also backflowed through drains in the adjoining apartment where damage was even more extensive. I have been told it was from a build up of sand and cement which blocked the drain. I have to replace my carpet and unfortunately overlooked contents insurance which after realising my mistake although too late I have since taken out.

I am told that the strata insurance will pay for next doors expensive replacement of parquetry as it is a fixture and also carpet in the common area but not in my unit. I have written to the executive committee and asked as the damage was related solely to a common property fault, which they do not deny, if a fair and reasonable compromise could be agreed on.

They declined saying they couldn't make exceptions. As well as seeming
ethically unfair I have been told that just because I did not have insurance does not mean the owners corporation is not legally liable for damage caused by common property. As it is a health issue the carpet in the affected area of the common area and my unit has been taken up but there is still a bad odour and some concern about the skirting boards.

I do not have the funds at present, so would have to borrow to buy new carpet so I would be really grateful if you could advise me if there is an easy option to claim for the cost or even partial cost of replacing my carpet without incurring legal expenses.

I am not sure if it is related to the sewage blockage but the building has undergone a major refurbishment of the pool and gym which my apartment is directly over so I was the most affected of all units in the building by noise and vibrations from jackhammering and as I work shift work was forced to sleep elsewhere when I needed to sleep during the day.

I never complained about this or any other issue so feel perturbed by the lack of return goodwill. Any advice would be very much appreciated.