Hi there and welcome
Can you please remove the power to the base unit and remove the batteries from the handset.
Then let it sit for 10 minutes, connect it back up and tell me if it now keeps the Date and Time please.
Hello there I am another Expert.The problem is that your telephone is receiving the time & date from the incoming Caller ID signal. This signal is incorrect because your telephone company is sending you the incorrect signal. Please go in to the time setting on your telephone and change the time setting from the default "Caller ID" to the Manual setting. Then you can set the time and it will not change. Hopefully your telephone company can correct the incorrect time being given out by their equipment.
Let me know the results of my instructions please.
Hello please ignore the other Expert. He is incorrect.
Let me know the results please