"no service" on iphone 5s

[mrsteen40]

My BT Sim worked fine when i entered it in a iphone 5s then suddenly the message "no service" appeared and in setting Carrier is unavailabler and Network is unavailable...no information is shown under the Mobile data setting and ive tried synching the phone with itunes on my pc and the software is up to date...somebody said i may need the BT settings for iphone but at the moment i have a nessage "you may not make/recieve calls or use mobile data until a update is installed....i was onto Apple support who said it is a carrier update needed....my sim works fine in my old Samsung android mobile....im very frustrated polease help

[stevebrass]

Have you tried removing the sim - giving it a GENTLE wipe - and replacing it?

[mrsteen40]

Spoiler

Tried that no joy and it works fine in my old Samsung mobile

[imjolly]

have you tried setting up BT APN

https://apn-settings.com/uk/bt-mobile-apn-settings/

[stevebrass]

https://support.apple.com/en-gb/HT201270

[mrsteen40]

When I click on Settings ...mobile data I just get a blank screen and network and carrier are both unavailable.I did a factory reset and wondered if I then needed the BT settings sent to my iPhone but I cannot make or receive calls and
assume the same goes for messages?