class column-half not working

Why my form does not use column-half & column-half
using WP 4.7 and the newest Contact Form 7 4.6 installed
I had Contact Form 7 Style plugin installed , but uninstalled it after i recognized i can do that without it.

<div id="responsive-form" class="clearfix">

<div class="form-row">
<div class="column-full">Name * [text* your-name]</div>
</div>

<div class="form-row">
<div class="column-full">Company * [text* your-company]</div>
</div>

<div class="form-row">
<div class="column-half">Email *[email* your-email]</div>
<div class="column-half">Phone *[tel* your-phone]</div>
</div>

<div class="form-row">
<div class="column-full">Message [textarea your-message]</div>
</div>

<div class="form-row">
<div class="column-full">[submit "Send"]</div>
</div>

</div><!--end responsive-form-->