Just after I booked the plane ticket with my mobile phone, I received a refund message. What happened?

In this case, you should be vigilant. It's probably a scam artist's means. You won't send a refund message after booking the ticket. It can be considered as a virus message. If it can't be well identified, the harassment interception function in Tencent's mobile phone housekeeper can identify such fraudulent short messages, thus warning netizens and avoiding being deceived.