Difficulty reformatting 3.5" floppy disk

Long story short, I have been trying to erase the data on a floppy disk completely and add a few (compressed) audio files onto it after erasing. At first when I deleted data off of it, it seemed that it was not deleted completely because it still showed the amount of available data as though there were still files on there. So, I tried to use Disk Utility to erase the floppy disk completely and reformat it. This did not work, and instead made the floppy disk apparently unreadable. The reason why it did not work is because every time I tried to erase and reformat it, it gave me the "MediaKit reports not enough space on device" error.

What should I do to fix this?