Answering Machine
noun
You hopefully know that this has something to do with housesitting (留守番). So, a telephone (電話) that does housesitting for you is what? It's your answering machine.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
留守番電話にメッセージを残しました。
I left a message on the answering machine.
トーフグのオフィスに何度も何度も電話をしていますが、いつも留守番電話なんです。
I've been calling the Tofugu office over and over again, but I always get the answering machine.
留守番電話にコウイチから明日飛行機でハワイに行くというメッセージが入っていました。
On my answering machine, I got a message from Koichi saying he's flying to Hawaii tomorrow.