Phone saying not registered on network

[Maxinne87]

Hi I have an unlocked S8+ saying not registered on network I have been to three store they checked all setting and my sim works in other phones. I done all the resets and even a factory reset and still getting not registered on network. I'm only able to use Wi-Fi. please help

[gratiot]

I want a new phone.  I have had trouble with this one and the latest thing is it is saying is "not registered on network'

I am completely dumbfounded on this one!

I ama senior citizen and this is causing me a lot of aggravation.  I am not able to call anyone. I LIVE ALONE1

PLEASE HELP ME AND GET ME A NEW PHONE.

THANK YOU.

JOAN MCROBERTS