I am a freelance designer and a professional developer. I speak English and Spanish and I can help you in all your requirements about Contact Form 7 WordPress Plug-in.
I can fix Contact Form 7 plug-in errors like "This contact form has a configuration error" or "This email address does not belong to the same domain as the site."
This is one of the plug-ins more useful that allows you manage multiple contact forms, plus you can customize the form and the mail contents flexibly with simple markup.
The form supports Ajax-powered submitting, CAPTCHA, Akismet spam filtering and so on.
Also I can fix errors in other plug-ins (configuration and PHP errors).