Membership plugin upgrade has locked me totally out of wordpress

So I have upgraded the membership plugin to the latest version so it would be 3.8.1 compatible. Since upgrading I have been totally locked out of Wordpress and now no one can log in and also all of the data behind the members area is open to anyone to view! Can someone please help me? I have tried deleting the membership plugin from FTP as well as repairing the SQL database, I am totally at a loss now for what was a standard install of the membership plugin and a standard upgrade.
Thanks