Sender shows as NOTICE when sending sms from a dedicated Indian AWS pinpoint phone number

I have purchased a dedicated AWS pinpoint long code for India (ie. An Indian phone number) for $120/mo. I'm not using any keywords. I've enabled two way sms on it. I'm able to receive messages on it and send messages, however when I send a message, the sender id shows up as NOTICE to the user.

Thus a conversation is not possible because while to user has to send a message to the dedicated long code, they receive a reply from a different number.

eg. When I send this message:

{
   "ApplicationId":"6b07b70b18714cf6ba60fb5446123456",
   "MessageRequest":{
      "Addresses":{
         "+914321321321":{
            "ChannelType":"SMS"
         }
      },
      "MessageConfiguration":{
         "SMSMessage":{
            "Body":"Your message was received, we will contact you shortly. ",
            "MessageType":"TRANSACTIONAL",
            "OriginationNumber":"+911234123123"
         }
      }
   }
}

The person receiving it sees it from sender "NOTICE". Even if I explicitly specify the senderId to be the same as the origination number. ie. I add ,"SenderId":"+911234123123" to the above, the behavior is the same.

Am I missing something, or is the AWS Pinpoint dedicated long code two way sms functionality broken in India?

This use case should be supported according to the AWS docs here: https://docs.aws.amazon.com/pinpoint/latest/userguide/channels-sms-originating-identities.html

Solution

I've found that this is not possible on all SMS api providers in India and I experienced the same behaviour on multiple different SMS api providers (aws/textlocal/some other). I also found a picture in the docs of one provider that showed this was not possible.

ie. India telecom infrastructure does not allow responses from long codes.

The infrastructure does allow responses from shortcodes, but sending a sms to a short code charges customers Rs 3., while a customer sending a message to a long code is billed at their standard sms rates.