Unicom's mobile phone will automatically reply to messages such as 10 1, 2082 to 100 10. What is the reason?

Hubei Unicom mobile phone users edit 10 1 send to 100 10 to check the phone bill and balance of the current month, and edit 2082 to check the balance of 3G packages. If it is an automatic text message, it may be that the phone comes with it or the third-party software has set up the automatic inquiry function of the phone bill, and the program automatically obtains the information of the phone bill and the package.