A phone that keeps ringing after the call ends

I'm sitting at my old dispatch desk but the room is underwater, or maybe just very quiet. The line rings and I pick up and it's a voice I know I should recognize, but every time I answer, the voice gets softer, like it's walking away from me down a long hallway. I keep saying 'stay on the line' and the phone just keeps ringing anyway, even after I've hung up. When I woke up my own voice was hoarse, like I'd been the one calling out.