LINEBotのカルーセルメッセージが表示されない

var LINE_TOKEN = "トークン";
var LINE_URL = 'https://api.line.me/v2/bot/message/reply';

function doPost(e) {

// Jsonにパース
var json = JSON.parse(e.postData.contents);
// 応答用Tokenを取得
var replyToken = json.events[0].replyToken;
//返答用メッセージを作成
var reply =　null;
// メッセージを取得
if(json.events[0].message.type == 'text'){
var userMessage = json.events[0].message.text;
}

if(userMessage == "指定した文字"){

var babbleMsgs = [];
for(var i=0 ; i<3 ; i++){
   var babbleMsg = {
     "type": "bubble",
     "hero": {
       "type": "image",
       "url": "画像のURL",
       "size": "full",
       "aspectRatio": "4:3",
       "aspectMode" : "cover",
       "backgroundColor" : "#f0f0f0"
     },
     "body": {
       "type": "box",
       "layout": "vertical",
       "contents": [
       {
         "type": "text",
         "text": "a",
       },
       {
         "type": "text",
         "text": "b",
       }
      ]
     },  
babbleMsgs.push(babbleMsg);
}
  var reply = {     				
    "type" : "flex",
    "altText" : "this is a carousel message",
    "contents" : {
                 "type" : "carousel",
                 "contents" :  babbleMsgs
    }				
  };    
 someMessage(reply,replyToken);

}
}
}

function someMessage(text,place) {
var headers = {
'Content-Type': 'application/json; charset=UTF-8' ,
'Authorization': 'Bearer ' +LINE_TOKEN
};

var payload = JSON.stringify({ 
  'replyToken': place ,
  'messages': text
  }) 

var options = { 
  'headers' : headers ,
  'method' : 'post' ,
  'payload' : payload }; 

// メッセージを応答 
UrlFetchApp.fetch(LINE_URL ,options)

}