Why do you call me when my cell phone is on, but I get a text message?

It may be because your phone reception signal is not good, which causes the network to recognize that you are turned off or out of service area, and the system will automatically call you to remind you.

See if people around you and you can use a network phone signal. If so, that's the problem in your area. If not, you'd better go to customer service to check your mobile phone.