Update for cellular service won’t go through. Cannot use the cellular part of my phone after update installed

Greetings, Terriy55.

Welcome to the Apple Support Communities. We can understand why you’d want to resolve the issue with having no service on your iPhone. 

Start by working through these steps: If you see No Service or Searching on your iPhone or iPad 

If the issue continues, consider providing more detail. 

• Which iOS version are you using?
• Do you see No service or Searching?
• Have you contacted your carrier?

We hope this helps! Thanks for being a part of the community.

Sincerely.