This used to be a regular complaint on te boards. The problem is that the Australian made Ugg boots can only be sold in Australia as the original makers did not register the trademark internationally. A US firm jumped on that error of judgement and registered the name in all other countries. Because ebay is a US company they have a blanket ban on any Ugg boots not covered by the US copyright. 

While it will almost certainly be only those second hand ones that are reported that are removed once you have had a listing removed it is just not worth it to try listing them again as you risk more defects and the suspension of your selling rights.

There were many attempts to get ebay to change this policy for sellers who did not sell to other countries but they all fell on deaf ears I am afraid.