Make field required

Hi I have this code in function.php

add_filter( 'woocommerce_billing_fields' , 'make_order_notes_required_field' );
function make_order_notes_required_field( $fields ) {
    // Set in the array your targeted product category term(s)
    $categories = array("company");

    if ( is_product_category_terms_in_cart( $categories ) ) {
        $fields['billing_company']['required'] = true;
    }
    return $fields;
}

It make Company name field required when “company” category product is in cart. And it works fine. But when I instaled your plugin (to add custom field) code stopped working. I tried “_billing_company” meta but without succes. How to make it work again with your plugin?