A customer of ours was having someone develop a site on Wix.com and that person is now permanently and suddenly unavailable. They have a login to what looks like a test site which they have someone modifying, but that isn't the same as the one that www.domain.co.nz is pointed to. 

With some platforms there is a test site and live site and you can publish your test site to the live site, but not being a web developer I am unsure how wix works in this regard. 

I see a transfer option to transfer to another account, but I am unsure if this is how you would "normally" do it. 

Anyone got any pointers?

cheers