Hi, Nandie21 kindly note that your device may need to booked in for a Software reload. It seems like the current software loaded on your device is malfunctioning. Please go to the below link to locate the closest Authorized Service Center to you.
You can also backup using Smart switch and then factory reset your device. Herewith Smart switch link:
Samsung Galaxy A12
In the meantime, my phone is almost useless when not at home.
This is the reply I received from my wireless carrier regarding "no registration" when out of my home area:
Please be advised that we are waiting for Samsung to push through software updates and that could also be causing the issues you are experiencing. Samsung has let us know they are pushing them through in batches and will be doing this shortly but did not give a time or date when this will occur.
To find when your specific device will receive the Samsung update you can go to unionwireless.com and click on “Network Updates”.