Controller in subfolder

Hello all, I'm studying how to separate my project so that my Controllers don't get too big, with many methods and parameters in each method, wich could cause a tremendous headache in future development. For doing so I wish to create subfolders inside the /app/Controller folder, and save my Controllers there, but I'm having trouble defining the Route for them, here is what I've tryied:

$routes->add('configuracoes/callcenter', 'Configuracoes/Callcenter::index');
or
$routes->add('configuracoes/callcenter', 'Configuracoes\Callcenter::index');
or
$routes->add('configuracoes/callcenter', 'App\Controllers\Configuracoes\Callcenter::index');

But all I get is:
"Controller or its method is not found: \App\Controllers\Configuracoes\Callcenter::index"

My folder structure is just like this:
App
-Config
-Controllers
--Configuracao
---Callcenter.php
etc...

Any tips?