How to tell the police when the mobile phone card is monitored?

Tell the police directly that you are being watched, and then provide the evidence you know.

First of all, the object of monitoring is not your mobile phone, but your mobile phone number. It is not advisable to change your mobile phone. You can change your mobile phone number. Then tell your friends your mobile phone numbers one by one, and when you find that you may be monitored again in the future, you can target who is listening. Then take corresponding measures to adjust. There are indeed some monitoring devices on the internet now. Listeners should listen to some numbers after buying equipment. Out of curiosity, they want to listen to other people's numbers at the same time, so this person is probably a friend of yours.