How to check whether your mobile phone number is connected to someone else's for free?

Check whether your mobile phone number and other people's mobile phone number are Unicom toll-free numbers as follows:

1. Log in to Unicom's online business hall through a computer or mobile phone client, enter your mobile phone number and password, and then you can query related businesses after logging in. 2. The mobile phone sends a text message "4 12" to 100 10 to inquire about the mobile phone package and its specific usage. 3. Call Unicom's customer service phone to choose manual service, and ask the staff to help you inquire. 4. Bring valid certificates such as the owner's ID card to the Unicom business hall to inquire about related business. How to check whether your mobile phone number is connected to someone else's for free?