Unable to make or receive calls

I have an iPhone 7 and I updated it to 12.1.4 a few days ago. Everything was fine before then. Now, I can’t make or receive any calls. As soon as I answer or make a call, it says call failed even though I have service and data. I also wasn’t able to make calls on Snapchat but I updated it and it worked fine. I still can’t make any calls, Facetime, Audio, or regular calls. I tried resetting my network, making space on my phone, reinserting my sim card, forced a restart. Nothing worked.

(If I have to reset everything on my phone, can all of my stuff be backed up by my iCloud backup without a computer?)