My iPhone 5 update iOS 8.3 to 9.2 but it cannot update

Hello AungKoLinn,
Sorry to hear that your iPhone doesn't have service. Let's see if we can get it sorted out.
I would start with looking at the settings to make sure cellular data is turned on. If it is and still not working, try restarting your iPhone as well as reseating the SIM card. Take a look at the article below for some additional troubleshooting if the previous steps do not help.
If you can‘t connect to a cellular network or cellular data
https://support.apple.com/en-us/HT201415
Let me know if this helps
Take care