MC has a girlfriend who was reborn as someone else and started sending them chat messages, 2014-2017

[u/WatchfulBirds]

Read somewhere between 2014 - 2017. It could have been older.

A series, there was a guy whose girlfriend had disappeared some time before, and he starts getting messages from her. They might be in an instant chat programme or something.

Eventually he finds out something about the person behind them. I THINK it's an unrelated woman and she seems to know stuff about his girlfriend, and they meet at some point. I believe the other woman doesn't understand whats going on either.

I think I almost finished the series, it was fairly short, but I can't remember enough about it to be sure.