After handover gyprock repair & maintenance painting issues

We got our own painting contractor to paint walls after handover.
Handover was 15 months ago.

Subsequently we had a large number of gyprock problems with bubbles, cracks and unevenness on three walls.
As this happened during the maintenance period the builder sent their ceiling contractor to repair all the problems.
The walls have been sanded, repaired and retaped in places.

The walls now need re-painting to make them as new again.
My question:- WHO is responsible for supplying the paint - The builder or us?

The building commission are unable to give me that information without first doing a written complaint which can take up to 6 weeks he said! Can they give me a basic simple answer, NO arrrgh

So if any of you guys have had this problem or know our rights, please enlighten me.