Our detectives are back with the following intel on this WordPress site
The site is using two themes, one child and one parent. The child theme is based on the parent and often custom to the site. The parent theme is X theme by Themeco .
We could identify 7 plugins (there might be more) - Contact Form 7 , Cornerstone , W3 Total Cache , WooCommerce , woocommerce-facebook-share-like-button , Yoast SEO and WPB Product Slider for WooCommerce
Make all of your modifications to X in this child theme.