Help you how? You don't seem to have a problem, just a misunderstanding of how partitions work, and I thought we had just cleared that up. If you mean that you made your disk too small then see the FAQ:
How to resize a Virtual Drive.
First however I'd look for a guest tool which lists all of the partitions on the drive, with some information about each one (purpose, filesystem, current fill factor). I can't make out what the number you've indicated (at the top right of your screenshot) is supposed to be. Without knowing what partition (if any) it relates to it really doesn't mean much. All I can tell you is that it seems to relate to a 1000MB partition you must have created somewhere in the guest OS. Perhaps some kind of hidden system or tools folder tree - I don't know Kali.
Speaking of which, a topic which mentions "Kali Linux" in the subject line IMHO doesn't belong in the "Using VirtualBox" forum. Moving the topic to "Linux Guests".