[OT] Dodgy Viet Bakery

I need on what to do about an event at a Newtown (NSW) bakery 30 mins
ago. I bought a custard tart but I could tell once she handed it to me
that the top was dark yellow so it was old (yesterday's). I folded back
the foil plate thingy and the crust was all soft, moist and fell apart.
I went straight back and asked for a fresh one. She says 'All same, all
same... baked this morning' etc but she gave me a new one. The fresh one
was, as expected, not prone to falling apart and the custard's surface
was a light yellow.

My question is does this happen often? Has it happened to you? Should I
drop it or follow it with authorities? And who then, hypothetically, is
the relevant agency in NSW? Please enlighten me.