My LG mobile phone changed a battery. Why are there no text messages and phone numbers?

The reason is this: the mobile phone is divided into two storage areas, one is ROM area and the other is NVROM area. Our phone book and personal information are stored in the RVROM area, which is an area where information can be written and deleted. If our mobile phone rarely loses the phone book or personal information under normal power supply, then we usually have a small spare battery in our mobile phone to protect your stored personal information from being lost in case of sudden power failure. However, when the mobile phone is turned off for a long time and the spare battery is exhausted, the information in the NVROM area may be automatically lost. And for reference!