I have already deleted LOTS of files but it is still full.

I've deleted almost one GB of files and then went to the Trash and deleted them. They should be gone and not counting against my storage. I have logged out, opened a new browser session, and logged back in. Yet, my account storage is still maxed out and I cannot upload a document that I need to send to a colleague. Is there a certain amount of time that I need to wait? How can the space to be available again?