Files and folders that are deleted will be in the Trash folder and still counting towards your quota until they are permanently erased, as shown below:

Step 1:  Click on the Trash folder.

Step 2:  Click on the action menu icon for the file/folder you want to permanently erase and select the “Erase” option.

Step 3:  From the warning window click the “Yes” option.

The file/folder selected will now be permanently erased and you will see a confirmation message.