Download interrupted an app from the apple store on a Mac
This is one of those situations where it is relatively easy to force a download to start over… but not vice versa.

If a resumable download is interrupted, then re-starting will automatically resume - unless you have changed browser or cleared its cache [even then a local ISP node may have it cached &amp; rapidly restore the first part], or opened up a brand new connection which the server doesn't recognise as belonging to the original download.

The issue - I suspect, I am no expert in mobile data communications - is that over a mobile connection, it is harder to re-establish that it is the same connection &amp; route to the original download… so it starts over.
I would guess that once that 'trust' has failed, you have no alternative but to start over.