I just did the stupidest thing: I created a blog for my dad and wanted to invite him to be an administrator. Because I'm new to WP myself, I thought that the examples that were in the invite new users box meant that you were supposed to enter the person's name and then their e-mail address. So I entered my dad's first name, followed by his e-mail address. It turns out that I accidentally invited this person whose username is the same as my dad's name, and I have no idea who that user is. Because I assigned him Admin privileges, I'm afraid that he/she might delete the blog or us as users. Is there a way I can undo that invite? Or is there a way I can get in contact with that person and ask him/her to please disregard that invite?
The blog I need help with is radioantigo.net.