As the unsolicited advice you have received was provided by very (generally) experienced members (or at any rate neutral observers), it might not hurt you to heed the advice.

Good thing it's a hobby as the first rule of retail is "The Customer Is Always Right". We all know that is untrue, but it doesn't hurt to use it as a rule of thumb.

Your terms are only relevant where they are in accordance with Australian Law and, as a subset, where they are legal, with the Terms and Conditions of eBay you consented to when you joined.