If you loved Phone, try Nightmare
A bridge between a film you've already seen and one most people haven't. Nightmare has roughly 5.9× fewer votes than Phone — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Ahn Byeong-ki, and they sit in Horror / Thriller territory. If that's the register that drew you to Phone, the second film will land in a comparable space — through a different lens.
What Nightmare is
Rainy Seoul streets at dusk a cassette tape Hye-jin's reunion with Eun-ju ends in a fatal fall Ahn Byeong-ki directs this eerie thriller.

