Why can't I call someone who shows an unknown number on my mobile phone?

If your Unicom number doesn't have caller ID service, others will display "unknown number" when dialing your number.

You can use the floating window on the right side of the online business hall of China Unicom > Customer Service > Transfer to Labor;

China Unicom mobile phone business hall APP > customer service > my customer service > transfer to labor;

Wechat official account "China Unicom micro hall" > 00/ to manual, access online customer service to verify whether your number has caller ID service.