How can I free disk space on the device to get it back into communication?
You should delete the Applications that you purchased from the AppStore.  You can download them again for free. Also, delete the  Applications you don't need.  If you go to Settings/General there is an option that reads iPhone Storage. Open that and give it time to completely load. At the bottom, it will give you a listing of all your applications and the size of them. Check and see if you can delete any of the large ones.