Here are a couple of things to check…
- Note that your Google quota is not simply a “Google Drive quota”. It is used by other things in your Google account – including GMail, and Google Photos (which your phone might be automatically uploading to). More information from Google is available here.
- If you send an item in Google Drive to the ‘trash’ folder, then it still uses quota. You need to remove it entirely to get the quota back.
Posted in: Google Drive, Troubleshooting