Buyer won auction but gave an Australian address.

Hi not sure what to do. Just had an auction sold last week and buyer paid after a couple of days with a NZ shipping cost of $6.50 urban but then unexpectedly sent an address for Melbourne? I went to the post office to check the cost of shipping this item to Australia and the cost was around $30 dollars. Nearly more then the item itself. They have not been in contact with me at all and so i had no idea they resided in Australia before or after the auction till the address was sent. Not sure what to do. Can I refund them the whole purchase and hopefully get my success fees back or is that not allowed? Am i required to complete this sale and ask for more money for shipping? Thanks