First of all, Hasbro Pulse only deals with America. That's why they will not have anything to do with a non-American customer.
Our stock in Australia didn't come from America, it came directly to Australia through Hasbro Australia, like with any other Transformers toy at an Australian retailer.
You have to deal with Hasbro Australia. It is their responsibility with all products sold within Australia that they imported, and if it requires Hasbro in America to help out, the Australian branch will be the only Australian people that they will talk to.

Secondly, you sold the item sealed AFTER it was no longer being sold. It is now a secondary market sale and since you aren't a retailer, it isn't your responsibility to make sure the product is perfect, or make amends if you didn't intentionally sell a defective item. If it was a year later, or any other sealed Transformers toy that is no longer in stores, the buyer has to accept what they get when they open the sealed box. The fact that this has just been released is giving the buyer a slim chance that Hasbro might be able to provide a replacement part... but that won't last for much longer, because they can't be expected to be providing replacement parts for toys that are no longer available from months or years ago.

The fact that you are trying to do something to resolve the problem should be thanked by the buyer, because they still have a toy that is going to be worth a lot more than what they paid, even with that one small defective part.
Not to mention, you had it stated clearly in your listing, that if there are any problems, you can't know because it is sealed, and you can't be expected to fix it.


What I would probably do if I was the seller, is give them a photo of the EB Games receipt, and tell them to contact Hasbro Australia for a replacement part or advice (and they would have proof of purchase of the toy, even if it wasn't actually them who bought it directly from EB Games). And if you sold it for over $1000, maybe refund $100 or so to compensate for the hassle... but beyond that, I believe that you have already done enough for a sealed second-hand item, even under Australian Consumer Law.