My mobile phone receives fixed short messages from other cities every day.

I think you dropped your original mobile phone and it was used by someone else.

Anyway, people in that city are using your old mobile phone.

According to the content of your short message, because your original mobile phone has anti-theft function, your current mobile phone number is bound to the anti-theft function of your original mobile phone.

When a strange card is inserted into your original mobile phone and turned on, the anti-theft function will automatically start the alarm function and automatically send a short message to the mobile phone number when you are bound by the strange card.