Who issued the Notice to Comply? If the strata manager has been delegated to do it, they can issue the Notice to Comply. Otherwise, you have to hold a meeting of the owners corporation (or strata committee) to pass an ordinary resolution to issue that Notice to Comply. Make sure you have evidence of a motion passed at a general meeting, if you did not authorise the strata manager to issue such notices.
Refer to Strata Schemes Management Act 2015 sections 146 and 147 for the exact rules.
Then google “NCAT application strata” and scroll down to a large heading “Penalty” which has a bit more guidance.
If your strata manager is trying to put you off going to NCAT with the $20K cost, can you ask your secretary to do it instead? An application costs a bit over $100. I hate the idea that you’re doing their job for them.
There are laws about “abandoned goods”. You could research that and see if you could simply pick up the rubbish and put it in the nearest red rubbish bin for council pick up. The drawback is that they might get the impression you are a free cleaning service.