Gedeelde audio

I kept getting a call from an unknown number every night at exactly the same time, 2:17 AM, and at first I ignored it because it felt like a scam or a glitch, but it never stopped, it rang once every night without fail, so one night I finally answered and there was nothing on the other end, just quiet breathing, not loud, not rushed, just slow and steady like someone was standing right next to me, I hung up immediately but a few seconds later I got a message from the same number that just said l