Their website has been up and down lately, not sure of the reason. Always better to ring if you can't go in person.
Yes, Gold Stackers in Melbourne is still quite operational (why does that sound like Emperor Palpatine?) The website was being migrated over the weekend to a new hosting provider. Unfortunately a DNS issue resulted in some users being served the old disabled website, resulting in timeout messages appearing for those visitors longer than expected. Was compounded a little by the issue spilling over into Sunday.