Why does the call drop every time I Face-time someone, but lets me text them?

The call drops every time I try to FaceTime someone. It allows me to text them and send pictures but not call. If someone is ringing me or if I ring them, it drops as soon as one of us answers.

My phone also isn’t recording my voice when I film videos, so it could be an audio issue. Though I can hear videos and music perfectly fine, no one can hear me. When I try to film a video with me talking, the audio symbol is grey with a line going through it.

Someone please help, I don’t know how to fix this issue.