Marvin has several ways to recover deleted items. If you just deleted the item, try pressing Ctrl/Cmd + Z to undo.
The next place to check is the Trash area in Marvin (Menu → Trash) on the same device where you deleted the item.
If you have recently made a backup, then you may be able to recover the item by restoring a backup. This is often not a great solution since you've probably made lots of changes to Marvin since this item was deleted, even if you're using the desktop app with its automatic weekly or daily backups.
If you remember the title of the item you're trying to recover, you can use the
SEARCH tool to look for it. First, go to https://app.amazingmarvin.com/pre, then follow this guide to open the console. In the console tab, type
SEARCH("Floss") (if you're looking for an item called "Floss") and press enter.
Hopefully Marvin will find an item with a matching title and print out "Found" followed by some data:
Click the small chevron (triangle) on the left to expand it and view data about this item:
This tool doesn't yet provide a way to re-create the item, but it may be helpful for remembering what the note was or when it was due! Please contact support to let us know whether it worked for you.