An accepted request is not the same as a delivery receipt. Check the message's later status, the sender's connection, and any returned failure reason. A testing number cannot deliver to a real phone even when its simulated request succeeds.
Keep the request and message references and the time of the attempt. Check the recipient and number type without sending the same message repeatedly. If no final status appears or a reported delivery conflicts with your test, send support those references and a redacted result. Do not include the customer's full message or conversation unless needed and reviewed.