Deleted files - how do I get it back?

My cache data was cleaned. I opened my RemNote page (saved in favourites) and used it as normal. Built a whole new document (4h work), which was deleted cause I was not logged in . I did no realize that - RemNote looks more or less the same when we are not logged in and there is no alert asking us whether we would like to log in or not, we can just start working with it as normal. Kindly asking how I could get a deleted file (which I lost while I was not logged in) back. Or, kindly asking RemNote to develop a kind of alert that warns us that we are not logged in…