Delete my account and blog

I have a WordPress.com account registered on my own domain: jackscotty.com. I have gone through many tutorials and directions to move my wordpress blog to a subdirectory: jackscotty.com/blog. Now everything is out of order and nothing seems to work. I want to delete it all, reinstall wordpress and just start all over. I can’t do this while the current account is still registered on my domain (jackscotty.com). How do I go about deleting this account or removing it from my domain?