Wow, that really sucks to hear. I had a had a good experience with them, and so has Luke_ENR34, which was why I went with them.
Did you pay cash or card? I am guessing cash since you said "they said i can only take my covers when i pay 200 CASH", in which case I would have asked for a receipt. If you paid card then you have a money trail you can use to go to the ACCC with maybe.
However if it was painted it wasn't their handy work, but should still liable for it as they suggested to use the painters, and organized it for you. Maybe speak to the ACCC anyway and see what can and can't be done.