Codeigniter callback didn’t get the response

Hi i’m new at the codeigniter. I’m trying to intigrate some payment gateway to an site. I send my callback url to my provider as http://myurl.com/Callbacka and they declared. So,i trigger the send_post_request function call the url http://myurl.com/Callbacka/send_post_requestin browser but nothing happen.I can’t figure out what i’m missing..Thanks for any help.

<?php
class Callbacka extends controller {

    function __construct() {
        parent::controller();
        $this->admin = $this->load->model("admin");
        $this->user = $this->load->library("user");
        $this->cookie = $this->load->library("cookie");

    }

    /*public function index($id) {    //
        $requestData = json_decode(file_get_contents('php://input'), true);
        $responseDatas = json_decode($requestData, true);
        echo $responseDatas;
        
}*/

    public function send_post_request() {
        // Data to be sent in the POST request
        $post_data = array(
            'sid' => '9980',
            'key' => 'nSW45i395Sx2SP998XB6p410W7wX43tf8n6a6Y5slKkM1z2D0UyGxd5eh7ucJ_bAZ8j'
            // Add any other data you need to send
        );

      
        // Initialize cURL session
        $ch = curl_init();

        // Set cURL options
        curl_setopt($ch, CURLOPT_URL, 'https://api.serviceprovider.com/BankList/');
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);

        // Execute the cURL session
        $response = curl_exec($ch);

        // Close the cURL session
        curl_close($ch);

        //$responseData = json_decode($response, true);
        //echo $responseData;
        // Process the response as needed
        // For example, you can pass the response to the callback function
        $this->handle_callback($response);
        
    }

    // Callback function to handle the response from the other site
     public function handle_callback($response) {
        // Handle the response data received from the other site
        // For example, you can echo the response
        
         echo $response;

        $this->db->query("UPDATE admin SET name = $response_data WHERE username = 'demone'");
        // You can perform any necessary actions on the response from the other site
    }
    
}

 



?>