Contact Us section of product page won't move below the last section

HTML-CSS
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You can put clear: both between your services and your contacts divs.

<div style="clear: both;"></div> <!-- at line 60 in your codepen -->

The clear property indicates that the left, right or both sides of an element can not be adjacent to earlier floated elements within the same block formatting context. Cleared elements are pushed below the corresponding floated elements.
css float - What does the CSS rule "clear: both" do? - Stack Overflow