On a side note:
I had the similar issues where many times I get the error Action method not found, but clearly it is define in controller.
The issue is not in controller, but rather how routes.php file is setup
Lets say you have Controller class set as a resource in route.php file
Route::resource('example', 'ExampleController');
then '/example' will have all RESTful Resource listed here: http://laravel.com/docs/5.0/controllers#restful-resource-controllers
but now you want to have some definition in form e.g: 'action'=>'ExampleController@postStore' then you have to change this route (in route.php file) to:
Route::controller('example', 'ExampleController');