plumbing maintenance

A flood caused major damage to my unit in a multi-unit dwelling
The CC&R's mandate maintenance of plumbing. None was ever done.
The HOA maintains it was the fault of an owner above me and even
if HOA maintenance the flood would have happened anyhow.Owner
maintenance manual generally speaks about plumbing maintenance being owner's responsibility
Answers?

The damage appears to be caused by the homeowner above me clogging the kitchen sink drain somehow,although that is still being
investigated. That homeowner was hardly ever there. He lives in another state. The HOA is aware of at lease 3 other incidents of a similar
nature involving plumbing problems in both of our 6 story buildings yet no preventive maintenance such as hydro-jetting the buildings
have been done. The buildings are only 6 and 4 years old. The HOA maintains 6 maintenance contracts for all other common elements.
but none for plumbing. A plumbing report will be issued that will say it is the individual owner's fault for not maintaining his unit and that
even if the HOA did maintenance it would not have mattered in this instance. Any other advice