You won't be actually deleting the "account", only the domain, so you could "start over" by re-adding the domain again without having to pay again.
That said, there is no need to do that at all. If you do, you will have to wait for DNS to update again when you "re-add" the domain. Just delete/move the file contents of the directories and "start over" by re-uploading your files (this time to the correct directory, to avoid this additional, and needless, delay.
Your FTP program should let you do that easily enough, and that's the way I would go if you are not comfortable/proficient using the shell.