Phone calls, video calls, voice notes have all stopped working!

Hi all!

I have an iPhone 7 Plus and have never had any real issues with it before. It is just under 2.5 years old and was bought new.

today, normal (eg, credit) phone calls stopped working. Also, internet phone calls and video calls (Skype, Facebook, and WhatsApp) and have stopped working. Voice notes will not record.

At first, the calls would connect but receive and give only silence. Now, the internet calls cut straight off, or show no “speaker” option. I was able to receive but not create phone calls successfully but now I cannot receive phone calls either.

Wifi and off WiFi. I’ve tried resetting the phone.

and, 2 days ago my power button stopped working. I do not know if that’s coincidental or could be related? In responses to this, I tried installing the new update iOS12.2 this morning. I would really appreciate any help, in causes and fixes. I live away from home so this causing me some real anxiety.