When your application submits a successful request to Cloud SMS's Batch API, you will receive a Batch ID value as part of the return code. (eg. 01010, b2,1493107120)
To check on the status of each individual MT message within your batch submission, login to Cloud SMS portal, and click on the API section.
Click on 'View only Batch API usage" to view the status of all messages submitted via Batch API. You can further filter the messages shown by clicking on 'Batch ID' and then entering the Batch ID value that was returned to your during the Batch request submission.