Legal Question in Business Law in California

You would have to sue UGG (not eBay) for declaratory relief that you are not infringing their trademark. Then and only then will eBay let you sell. Have a lawyer send them a Lawyer Letter and see if they back down.

Just because you are legally buying and reselling their products does not mean you are not infringing their trademarks. The right to buy and sell a trademarked product and the "fair use" right to identify the product as a branded product, does not give unlimited rights to the trademark. For example, are you using their logo in the eBay listings? Are you using their brandname (other than to identify the brand of the goods and always with a (r) designation)? Not allowed unless they grant permission. You need to figure out what it is about what you are doing that they object to as trademark infringement and then stop it.

What you may have to stop doing is selling their products, period.

Sorry to break the news to you. Manufacturers have a right to control who resells their branded products downstream. It doesn't matter that you are selling genuine articles purchased from the manufacturer or an authorized source. It probably doesn't make any difference whether or not you use the (R) symbol.

If you want to deal in products made and branded by XXX, then XXX has a right to require you to obtain authorization from them, and XXX can refuse to authorize you.

There is an exception known as the "first sale doctrine" which traditionally allowed a consumer buying an article for personal use to re-sell the article as "used" via a garage sale, to a pawn shop, as part of an estate, and so forth. The rise of non-traditional channels of e-commerce, including eBay and Craigslist, have created confusion and litigation as to how far the "first sale doctrine" goes to prevent people from running unapproved dsitributorships through electronic media. My opinion is that what you are doing is no protected by the first sale doctrine, though I hasten to add there are no federal statutes, no reguatory agencies with authority, and no really-applicable Supreme Court cases. There have been several recent U.S. District Court cases testing whether first sale doctrine applies to semi-pro eBay resellers.

I suggest you use a search engine to find "A Research Guide to Trademark and the First-Sale Doctrine on the Internet" by Benjamin J. Wilson, a law professor at St. Louis University. He doesn't really answer the question, but does give some research leads to sources of guidance on this evolving legal issue.

If time permits, I'll look at some of the cases mentioned by Prof. Wilson and post a follow-up answer if I see anything that changes my initial opinion that the Australian company is exercising a legal right in cutting you off.

Look at the Federal case called Australian Gold v. Hatfield at http://ca10.washburnlaw.edu/cases/2006/02/03-6218.htm

and in particular the court's discussion of the first sale doctrine.

The citation is 436 F.3d 1228 (2006).

Note that the Hatfields got hammered by the court - including punitive damages. I don't know the extent to which your situation is the same as, or different from, the Hatfields, but this and similar cases show the risks of reselling over a trademark owner's objection.