Hi @marc666 ,
Your Samsung phone reads the phone number originally assigned to the SIM card and if you are no longer using that number (such as when you've ported over your old number to use with the new SIM card) your phone will no longer know what number you are using. Your phone in this case will list your current number as 'unknown' or present the number originally assigned to the SIM card.
This information cannot currently be amended due to how the Android operating system registers a number to the handset upon first use. The issue may be resolved in a future Android software update, but until then rest assured that it has no effect on your device's functionality.
In regard to the chat features this has been removed on the latest versions of the Samsung Messages app. In order to use this you will need to use Google Messages.
