Thanks everyone for their help. A primary mirror has been setup by @Nadir and the secondary ones should resume sync’ing soon. Matej has contacted the administrator of an academic network, who’s agreed to setup a mirror too. This went better (and sooner) than expected. Well done!
April 16th 2018: Artix needs our help and we endorse every single positive attribute to the great work that they have contributed to the Open/Free world. This is a serious call for help, especially if you are either rich or working within a large computing organization, such as a major university you can help. Their single master repository server that their 4 mirrors depended on is gone. Here is their own announcement:
systemd-free linux community 