Today, despite 20 yuan's phone bill, I still can't surf the Internet, send text messages or make phone calls. What happened?

When the phone prompts "Unregistered Network": 1. I suggest you turn off your phone first, pull out your SIM card, plug it in again, and try again. 2. You can try another mobile phone. If it still doesn't work, you can go directly to the local business hall to find out the specific situation. If your mobile phone card doesn't work, you can confirm the following points: 1. Insufficient contact between SIM card and metal contact of mobile phone; 2. Whether it is 2. SIM card is damaged; 3. Is the location a signal blind area or there is no signal suddenly. Tips: I suggest you put your mobile phone card in another mobile phone to test it. If this still happens, I suggest you take your mobile phone card to the business hall for testing. Common reasons and solutions of mobile phone not answering the phone: 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. It is recommended to change your mobile phone or location and 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 the number has been roaming; 5. Try restarting or changing your mobile phone to see if you can answer the phone; 6. Bring your mobile phone card to the local business hall for testing or replacement.