When a group of girls are expelled from their high school for an explicit group chat they created, they make it their goal to get back at the snitch who got them caught.

I can see a few problems with the concept itself or at least the way it is described in the logline.

1. is this an ensemble screenplay? Because right now, we have no sense of who is the protagonist, who is antagonist. Is the one who wants revenge or is it the snitch who must go into hiding?
2. Assuming that the one searching revenge are the protagonist, they do not look like very sympathetic characters. That is not necessarily a problem for the movie itself, but the logline at least you want at least one reason you would root for the shade of grey character. For example in the TV series, Dexter, the main character was describe as a serial killer who targets those who have escaped the law. At least one redeeming quality.
3. The goal is very vague. Get back at the snitch. What does it means: boil her bunny, Kill her, get her expelled as well,
4. there is no sense of what the plot is really. A group of girl wants revenge after being expelled from school. What are they going to do about it? Gossip among themselves? Torture every former classmate to find the snitch?
5. From the way the logline is written, I cannot guess what genre is the movie. Is it a comedy, a satire, a drama, a thriller or even an horror movie? Based on the same concept of girls having been expelled want revenge, the movie can be made in all genres mentioned before. A good logline should give you clue to the genre, the historical context.