What should I do if I receive the original question of the text message?

You can call the local self-study office and ask them to check it for you. Generally, as long as the online registration is successful, it will be successful. The SMS notification was sent recently, and it may have been delayed or its database has not been updated to temporarily support your mobile phone number, so it was not sent to you, but to your friend's number. Is your number a new segment? If so, it may not be supported for the time being!