Complaint Against a Service

Woolworths Australia — Woolworths 20 multipack chips

I bought a woolworths brand multi pack of chip on Sat 14/12/2019 at Clifford gardens Woolworths in QLD
I opened the bag today 16/12/2019 as my kids wanted to have some chips. both of my youngsters wanted the supreme corn chips, I opened 1 packet there was corn chips, opened the next pack no chips whatsoever, only a big pile of flavouring.
And there was only 3 packs of these supposed to be 5 packets.
I have taken photos of the packet nobody else touched it, and I don’t like corn chips so I wouldn’t have eaten it. I would really like to know is what can be done to replace or fix this situation.