Pay Per View - can't login (Facebook/Twitter) turn off WP login

I'd like to allow people to login with Facebook or Twitter.

-When Facebook button is selected nothing happens.

-When Twitter button is selected, it shows a popup window, "Sorry that page doesn't exist" then it changes to "authorize ... to use your account." I login and it redirects me back to the page where I started.

-Login with Google and Wordpress works. I don't want to offer a link to create a user account (I get so many new users with weird email addresses = hackers).

Can we turn off login with Wordpress?