PHP Call to undefined function $name = call_user_func [closed]

Hello i have this issue but im not figured out why

Error: Call to undefined function Wachat() in /home/hexahos4/public_html/modules/addons/wachat/classes/WachatGateway.php:112
Stack trace:

#0 /home/hexahos4/public_html/modules/addons/wachat/controller/WhatsAppConfig.php(70):WachatGateway::GatewayList()

#1 /home/hexahos4/public_html/modules/addons/wachat/base.php(30): WhatsAppConfig->index()

#2 /home/hexahos4/public_html/modules/addons/wachat/wachat.php(156):require(‘/home/hexahos4/…’)

#3 /home/hexahos4/public_html/lakonage/addonmodules.php(0): wachat_output(Array)

#4 {main}

93. public static function GatewayList()
94.    {
95.        if(!function_exists("moduleConfigFieldOutput")) {
96.            require_once ROOTDIR . "/includes/modulefunctions.php";
97.        }
98.        if(is_dir(ROOTDIR . "/modules/addons/wachat/classes/")) {
99.            $handle = opendir(ROOTDIR . "/modules/addons/wachat/gateways/");
100.            $return_array = [];
101.            while ($file = readdir($handle)) {
102.                $file = str_replace(".php", "", $file);
103.                if($file != "index") {
104.                    $modfilename = ROOTDIR . "/modules/addons/wachat/gateways/" . $file . ".php";
105.                    if(is_file($modfilename)) {
106.                        if(!function_exists("gateway_" . $file . "_send")) {
107.                            require $modfilename;
108.                        }
109.                        if(function_exists("gateway_" . $file . "_send")) {
110.                            $name = $file;
111.                            if(function_exists("gateway_" . $file . "_name")) {
112.                                $name = call_user_func("gateway_" . $file . "_name")();
113.                            }
114.                            $return_array[$file] = $name;
115.                        }
116.                    }
117.                }
118.            }
119.            return $return_array;
120        }
121.    }

Gateway Wachat.php

<?php
function gateway_wachat_name()
{
    return "Wachat";
}
function gateway_wachat_config()
{
    $configarray = ["apikey" => ["FriendlyName" => "API Token", "Type" => "text", "Description" => "API Token];
    return $configarray;
}
function gateway_wachat_send($params)
{