Check SIM card
First of all, you need to check whether the SIM card of the old machine is normal. You can take out the SIM card, insert it back, or replace it with a new one. If there is nothing wrong with the SIM card, you can try to turn it off for the elderly and wait a few minutes before turning it on.
Call the operator's customer service phone.
If you still can't solve the problem after checking the SIM card, you can call the operator's customer service number. The customer service staff will help you check whether the SIM card is normal or not, and also help you lift the restrictions on the old machine. It should be noted that calling customer service calls requires SIM card number, mobile phone number and other information.
Brush unlocking
If the above methods can't solve the problem, you can consider swiping the card to unlock it. Unlocking the brush machine requires professional technology and tools. It is recommended to find a professional mobile phone repair shop or the after-sales service center of the mobile phone manufacturer. There are certain risks in unlocking the brush. If you don't know how to operate it, it may cause the phone to turn brick.
The situation that the telephone of the elderly is limited to emergency calls can be solved by checking the SIM card, calling the operator's customer service phone or swiping the card to unlock it. If the above methods can't solve the problem, it is recommended to contact the mobile phone manufacturer or after-sales service center for handling.