How to use /fb/sending/sendContent?

For now it looks like this:
{
  "subscriber_id": 1713298109,
  "data": {{
         "version": "v2",
         "content":{
             "type": "instagram",
             "messages": Â{
             "type": "text",
             "text": text,
             },],
         "external_message_callback": {
         "url": "https://doctor-dent-aidachatbot-c0e090c513c2.herokuapp.com/",
         "method": "post",
         "headers": {
           "x-header": "value"
         },
         "payload": {
          "id": 1713298109,
           "last_input_text": "text",
           "key": "value"
         },
         "timeout": 30000
         },
     }
   }
},
  "message_tag": "ACCOUNT_UPDATE",
  "otn_topic_name": "NO"
}

But I don’t need any tag and otn_topic_name.  I tried to remove them but another error occures. Tell me how to fix it please