Haunting, The - Two Voice Recorders Better Than One
When Eleanor is on top of the plank following the children's voices, note Dr Marro climbs the hanging stairs that start breaking and you can clearly see how his voice recorder falls and crashes against the floor. Some scenes later he dictates again on his recorder as if nothing had happened.
Why would they have a big important close up of him dropping his voice recorder. The reason they showed it falling was because thy could not call anyone for help without the phone.
I just watched the movie for the first time and you can clearly tell that he dropped the cell phone. Maybe you should watch the movie more closely next time.