Cron doesn`t run controller method

[Zenko]

Hello my Fat Free version is

    "bcosca/fatfree-core": "^3.8"

And I`m trying to send mail with cron letter by letter in the loop.

Before started, I downloaded cron.php from here https://github.com/xfra35/f3-cron/tree/master

And puted it to vendor/fatfree-core directory:

Here is my config.ini:

[CRON]

log = TRUE

web = FALSE

silent = FALSE

binary = php

[CRON.presets]

every-3-min = */3 * * * *

And here is my index.php

$fw->config($config_path);

$cron = Cron::instance();

$cron->set('Mail_send_job', 'Main_Controller->sendMailAction', '@every-3-min');

So when it started by task it returns an error:

===================================

ERROR 500 - Internal Server Error

Invalid class Main_Controller

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/base.php:2137]

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/base.php:2137] user_error()

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/cron.php:114] Base->grab()

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/cron.php:153] Cron->execute()

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/cron.php:167] Cron->run()

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/base.php:2222] Cron->route()

[D:/Programs/WebSrv/xampp/htdocs/vendor/bcosca/fatfree-core/base.php:1992] Base->call()

[D:/Programs/WebSrv/xampp/htdocs/index.php:32] Base->run()

And when I trying to start it manually says:

Nothing to do

How can it be solved?