Something might be wrong with the phone because it’s weird that no listeners have called in.
A listen someone, is someone who listens. This is a listener.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
For this word, most often you'll hear the word リスナー but this is a kanji learning site, so you're going to be learning yourself some kanji, you hear?