区块链不断发送回叫请求

I am trying to make blockchain receive payments system, every things is successfully except that blockchain keeps sending callback requests to my callback file althought iam echoing "ok" to stop this request

this is my callback file

                if ($order->btc_amo==$value_in_btc && $secret=="ABIR" && $confirmations >= 1){


                $savedata['confirmation'] = $trx_hash;
                $savedata['gateway_response'] = json_encode($request->all());
                $savedata['status'] = 'paid';

                //Update product sales
                $this->salesupdate($order->product_id);
                //Save order
                $this->neworder($order->user_id,$order->product_id,$order->price,$order->hash,$order->id);
                //Save user transaction
                $this->newusertransaction($order->user_id,$order->price);
                //Credit seller
                $this->creditseller($order->product_id);
                //add balance 
                $this->addbalancetouser($order->user_id,$order->price);


                $order->update($savedata);




                    echo "*ok*";





            }

note : every thing is work successfully except this problem

working with PHP 7.2 and laravel 5.5