Deleting Files from Phone App but keeping them on the cloud?

I use Adobe Scan - the free version.  I had an online chat with an operative from Adobe and she tells me that when I delete them on the app on my phone, they are also deleted from the cloud.  So that was clarified.  But since that call ALL MY SCANS have mysteriously gone from my phone (I didn't delete them).  What's going on?  The files are still on the cloud luckily, and perhaps I've got what I wanted but I wish to understand how to keep my stuff from disappearing in future.