The endings available in both versions are the following:
1: You end up alone, without any girls.
2: You end up with Ayaka, but you make a mistake in some decision, so you don't see the end of the story.
3: You end up with Kotomi, but without seeing the end of the story, the same as with Ayaka.
4: You end up with Reika, the same as with the other two.
5: You finish Ayaka's story without making a mistake in any decision, so you see the end of the story.
6: You end up with Kotomi seeing the end of her story.
7: You end up with Reika the same as with the other two.
It's possible that you're missing the two endings with Reika, since they're the hardest to get. If not, I assume you made a mistake with one of the girls.
Regarding the other endings in the paid version, these are:
8: You finish the story with Ayaka and Kotomi.
9: You end it with Ayaka and Reika.
10: With Kotomi and Reika.
11: The four girls end up together in a way that you discover by playing the game.
12: The four girls end up together in a different way.