This site is a bit cumbersome and less intuitive than some. It's a drag you can't delete a post. I've been caught by that too.
Click 'Edit', if still available, > click 'Go Advanced' > scroll down to 'Attach files' and click 'Manage Attachments.'
At the top of that box click 'Browse' and you can find a file on your computer.
Now, let's see your Limited !