No service and I want to re-install the new update

You cannot install an iOS update via cellular. Either use wi-fi, or connect the device to a computer with the latest version of iTunes. If you wish to restore to factory, you will have to use iTunes. Update your iPhone, iPad, or iPod touch - Apple Support

You need an internet connection to connect to the Apple Server.

Can you get on wifi if you have no cell service?

See if the tips in the following article helpp resolve the issue.

If you see No Service or Searching on your iPhone or iPad - Apple Support

If not, then see:

iPhone 7 Repair Program for "No Service" Issues