input post empty

my js function

Code:

function sendLogin(id, email) {
   $.ajax({
       type: "POST",
       contentType: "application/json; charset=utf-8",
       url: "http://www.plickapp.com/API/index.php/users/register_user/",
       data: "{'idfb':'" + id+ "', 'emailfb':'" + email+ "' }",
       success: function (result) {
            console.log("Ok " + result);
       },
       error: function (result) {
           console.log(result);
       }
  });
}

the frontend is hosted in another space (app, localhost, another server)
so i set the header in my controllers for accepting external request with

PHP Code:

header('Access-Control-Allow-Origin: *');
header("Access-Control-Allow-Headers: ACCEPT, CONTENT-TYPE, X-CSRF-TOKEN");
header("Access-Control-Allow-Methods: GET, POST, PUT, OPTIONS, DELETE");
header("Access-Control-Allow-Headers: Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With"); 


could be the .htaccess ?

-------- UPDATE ----------- 
sending data by GET it works.
example
my request

Code:

http://mysite.com/users/register_post_user/?id=5890459084523908&email=testemail

the result is 

Code:

Array ( [id] => 5890459084523908 [email] => testemail )

tested by URL in browser directly and by Postman....