Remove the item to prevent future downloading
With the Download Block, you have the ability to remove the file(s) after initially publishing them on your website. Anyone that has purchased the file or downloaded it from your site in the past that still has a download URL will lose access to the file.
To remove a file from your site:
Tap the Download Block that contains the file on the Grid Editor
On the top left of the file, tap the X mark
This will then remove the file from this block to prevent future downloads. Be sure to publish your changes after removing the file!