In order to have a better understanding of your concerns, could you please let me know the following:
Are you able to see the .odt files in your Dropbox account through the website?
Could you attach in your next reply a screenshot(without personal info) or send me a shared link of the image showing what you see when you click on the Dropbox icon that’s next to your computer’s clock?
In regards to your second query, are you creating a new document through the website, the desktop app, or the mobile app?
Could you also clarify what you mean when you mention that you retrieve the file?