How can I make sure my Dropbox files don't take up space from my devices?

Yes, of course.  Thank you for your reply.

I signed up a few days ago for the 2TB plan.  I'd been using the free plan for years & years before then.

I cancelled the new subscription immediately I discovered that an iOS application I'd been using (again for years) didn't work with Dropbox, even though it was set up to do so (it's called FileBrowser).  The designers of the app are looking at it presently to find out just why it won't work (although they sem to be as flumoxxed as me about why it's not working!)

Here's what they say : "The reason FileBrowser doesn't play your video and instead offers the Stream to Another App option is that the video is in a format that iOS can't play (FileBrowser uses the in-built video codecs to avoid licensing issues - other apps usually ignore these potential legal problems). "

I wanted to know in the meantime - and while FileBrowser are looking into all this - is whether the cancellation that I had subscribed to  (the 30-days' free trial) has gone through and when it will come to an end (a full month or in 28-days).

I also wanted to know that when I play anything on my iPhone (music files or videos), when it says "synching in progress" (or something similar) if my phone is actually going to be downloading the file to my device... as if so it's going to be pretty useless as I shall be running out of space imminently, making the whole process of me signing up to a 2TB plan worthless.

Sorry that this is all a bit convoluted but the Internet has got enormously more complicated since I first used it in 1996.

Thanks for your advice. Steve