Who pays for Common Property water leak damage?

Hi, our strata block was built in 2004.  Recently our Private Lot was water damaged from an obvious water leak coming from and through a Common Property wall (boundary wall) within our unit.  We have been told by the Strata Manager that the Owners Corporation is not responsible for the cost to repair the water damage caused to the plaster and paint on our side of this Common Property wall and that this is the Lot Owners responsibilty.

Luckily the leak occured in a tiled laundry and not our living area with carpet, otherwise we would be left with the damaged carpet expense as well.  I know these costs would be ours under normal “maintenance” circumstances, but surely if there was damage from a water leak clearly coming from a Common Property wall, any subsequent damaged caused to our Private Lot should be the Owners Corporations responsibility through an appropriate Insurance claim?  Any thoughts on this would be much appreciated!