Why is there a train ticket booked by someone else on my information? Is the information leaked? What should we do?

When booking online, you will enter the mobile phone number to receive information. If you didn't book a ticket but received the message, there may be several situations: 1, someone else's number is very similar to yours, and you entered it incorrectly; Your number has been used by others before, and he left this number on the 12306 train booking platform to receive information. For example: