My app is not released yet, but I want to test it with live ads before it's out to make sure that the Mobfox integration works properly. Can you please approve my publication?

We don't approve publications for apps that weren't released yet, in order to get a publication approved its URL has to lead to its traffic source (i.e. your app's page on the app store / your website). 
If you want to test you can use our blue test ad that you get automatically before you activate the publication (that's what they're for) - if you get it successfully you'll get the live ads successfully as well.