'No network service' on iPhone 7
No network service
iphone 7 network is not stable
[Re-Titled by Moderator]
iPhone 7, iOS 15
There was an inherent issue with some of the iPhone 7's. The hardware would fail leaving the phone without cell service. Apple acknowledged this and repaired it for free for many years. However, that warranty repair expired a few years back.
If your iPhone 7 no longer works with cellular, you will have to purchase a newer phone.
You might be able to take it to the Genius Bar to have it repaired, but I'm not sure if they still have the parts to fix it and if they did, it probably wouldn't be worth the price of repair.
It might be time for a new phone.
Genius Bar Reservation and Apple Support Options - Apple Genius Bar Reservation and Apple Support Options - Apple