Thanks for writing in!
Did you install 3rd party plugin that limits the login, monitor any unwanted login or a plugin security? If you have ftp access, please go to your plugins folder and manually renamed the 3rd party plugins folder by adding a
_ to the folder names so that it will be disabled. You should be able to get back to your WP dashboard once it is disabled.
If nothing is helping, please provide us your FTP access and WP access so that we can investigate further.
Hope this helps. Please let us know how it goes.