Last night (beginning at 3:20AM 10/01/13 AEDT) we experienced some issues surrounding Marketplace payment processes, search, and eSupport. We'd like to keep you all informed, and will be posting updates on the forums and on Twitter.
eSupport is now back up and our tech team are working hard to resolve all known issues. If you have had difficulty purchasing an item or submitting a support ticket since 3:20AM, please read through the forum post, and follow the instructions outlined there.
Thanks for your patience!