Gravity Forms Don't Save Form Entries in Database

snippet.php

<?php
/*
USAGE
add_action( 'gform_post_submission', 'mr_remove_form_entries' ); // ALL FORMS
add_action( 'gform_post_submission_1', 'mr_remove_form_entries' ); // SPECIFIC FORM (ID = 1 in exmaple)
*/
add_action( 'gform_post_submission_1', 'mr_remove_form_entries' );

// Deletes entries from the database on the specified Gravity Forms form(s)
function mr_remove_form_entries( $entry ){
	global $wpdb;

	$lead_id		= $entry['id'];
	$lead_table		= RGFormsModel::get_lead_table_name();
	$lead_notes_table	= RGFormsModel::get_lead_notes_table_name();
	$lead_detail_table	= RGFormsModel::get_lead_details_table_name();
	$lead_detail_long_table	= RGFormsModel::get_lead_details_long_table_name();

	$sql = $wpdb->prepare("DELETE FROM $lead_detail_long_table
							WHERE lead_detail_id IN(
								SELECT id FROM $lead_detail_table WHERE lead_id=%d
							)", $lead_id );
	$wpdb->query($sql);

	$sql = $wpdb->prepare( "DELETE FROM $lead_detail_table WHERE lead_id=%d", $lead_id );
	$wpdb->query($sql);

	$sql = $wpdb->prepare( "DELETE FROM $lead_notes_table WHERE lead_id=%d", $lead_id );
	$wpdb->query($sql);
	
	$sql = $wpdb->prepare( "DELETE FROM $lead_table WHERE id=%d", $lead_id );
	$wpdb->query($sql);
}