I think you managed to get some really cool creepy vibes going, loved the messenger idea and the added detail of other chats hinting at stuff you never let the player know about, it's a nice world building touch
Audio wise it is a little barebones, I think some ambience or some music could've tied the whole thing together a bit better
The biggest compliment I think I can give is that when it ended I wanted to play more of it!
Good job with the jam, hope you had fun with the project!