I’m not going to take sides on this, but here is advice for you.
Did they issue a notice to comply? A notice to comply is an official notice to another owner of a breach of a by law. It must tell you which by law you breached.
Any other notice you can ignore with impunity.
Once you get a notice to comply, you can choose either to act on it ie reduce the by law breach, or if you don’t agree with it do nothing. The owners corporation , without an order can’t touch you.
It’s then upto the owners corporation to take the matter further. First through mediation and then to NCAT.
If it gets to NCAT it’s up to the owners corporation to prove the breach. The lot owner can stay silent.
If you are found to be in breach of the by law, in the case you quote, the worst I expect is the tribunal would just tell you to comply by a certain date.