The issue might also be with a conflict if you are using Jetpack. Some other contact forms have offered this message:
Jetpack is a popular plugin that allows you to utilize many features of WordPress.com on your self-hosted WordPress site. I like Jetpack and use it on my many sites.
Unfortunately, Jetpack’s contact form module, newly introduced with Jetpack 1.3, conflicts with other contact form plugins
A typical problem is that Jetpack hijacks other plugin’s contact form shortcode. As a result of this, your customized contact form is replaced by Jetpack’s plain contact form, and the submitted message may be sent to an unintended destination.