Hi sure they can open a dispute but you can also dispute that they wont except payment and you have full intentions of paying as soon as they nominate an account so it will more than likely be squashed.
I doubt it will go that far if your seller does not ship to Australia it would be the reason you can not pay. It will be blocked. Try message them saying you made an honest mistake and did not realise they did not ship to Australia and your still willing to go threw with the transaction if they want to. And if they do not want to ship to you ask if they will do a mutually agree to end transaction. This will release you from any commitment and the seller will not incur any fees.
It would not be in the sellers interest to open a dispute against someone who was willing to complete a transaction or has not been sent a invoice. You have a good case so I would not be to worried . I doubt they will take action as your a willing buyer so filing a NPB against you wont really work. NPB = Non paying bidder. Which you are not if your willing to pay.
Good luck.
