Translation:The boxes are sent the moment they are ready.
Maybe it should be accepted, because "when" and "the moment that" are similar; but I think that "ברגע ש" has some urgency in it - at the moment the boxes are ready, they're sent - which I'm not sure "when" has. Also, moment=רגע so it's another reason to prefer this translation. :-)
Linda, you can switch browsers (and change your browser setting to desktop view/mode). I hate Google Chrome, but people seem to have better luck getting the audio to work there. Or try Puffin browser). It always works in the Duolingo app for me, where the browsers are hit and miss).