Which movie is this (horror movie with caller)?

I'm looking for a movie about 2 years ago on Netflix.

It was about a young woman who (I think) moved. One evening we started with the calls, at the beginning nothing was ever said and then there was an elderly woman who was constantly asking for a man who probably lived in this apartment (but he was already very long dead) , I think he died in the Vietnam War or had a mark of it).

The calls were at first harmless, but then became more intrusive and the older woman has always stranger things said and the young woman scared.

Unfortunately, I can hardly remember any more details, but maybe someone still knows the movie. 😬 By the way, it's not the movie "Unknown Caller".

https://www.imdb.com/...lmg_act_21

Many Thanks!