adishaked_my_pmpro_getresponse_custom_fields.php

<?php
function my_pmpro_getresponse_custom_fields( $fields, $user ) {
	// Get fields from Register Helper user meta
	$phone = get_user_meta($user->ID, 'mytheme_phone', true);
	$fullname = get_user_meta($user->ID, 'mytheme_fullname', true);
	$fields = array(
		'telephone' => $phone,
		'full_name' => $fullname,
	);
	return $fields;
}
add_filter( 'pmpro_getresponse_custom_fields', 'my_pmpro_getresponse_custom_fields', 10, 2 );