I see from your post that you're not able to make calls on your iPhone. Being able to stay connected is very important and I want to help guide you to a solution.
Take a look at the steps provided in this article called If you can‘t make or receive calls on your iPhone. There are quite a few steps listed that can take some time to complete. I recommend setting some time aside to do it when you are able to.
For some of the steps, it is highly recommended that you create a backup of your iPhone's data before continuing. This article called How to back up your iPhone, iPad, and iPod touch provides step-by-step details on how to back up you iPhone's data if you need to.