Unicom's mobile phone card can answer calls and text messages, but it can't make calls and send text messages, and suddenly it can't be used. What is the reason?

First, the common reasons why the mobile phone can't answer the phone and the solutions are as follows: [1] Check whether the mobile phone is in arrears, and it is recommended to pay for it; [2] Check whether the mobile phone is set with call forwarding, flight mode on and call barring. Suggest canceling and try again; [3] Check whether the function or signal of the mobile phone is normal, and suggest to change the mobile phone or try again; [4] If roaming to other places can't be used, it is recommended to check whether the local network signal is normal and whether roaming permission is enabled for this number; [5] Try to restart or change the phone to see if you can answer the phone; [6] Take the mobile phone card to the local business hall for testing or replacement. 2. The reasons why the mobile phone card cannot be used are as follows: 1. Insufficient contact between mobile phone card and metal contact of mobile phone; 2. The mobile phone card is damaged; 3. Is the location a signal blind area or there is no signal suddenly. Tips: You can try to put your mobile phone card in other mobile phones for testing. If it still doesn't work, I suggest you take your mobile phone card to the business hall for testing.