I went to one of these and got freaked out
That's the problem, you freaked out and left, even though they ask everyone multiple times at the beginning whether you are ready to stay for the full 10 days.
As someone who took more than one of these courses I can say that the single most important thing you should do during your first course is not quit. Strange things start happening to people when they are put into an environment where they can't do anything but eat, sleep and meditate. Your mind starts playing tricks on you and you start reacting to your thoughts. Wave after wave of anger, joy, confusion, happiness, sexual fantasies, tranquility, fear, etc, come and go. It's like your mind switches to different modes. You don't notice this during normal life, and that's the real beauty of these courses and centers. To give you an opportunity to observe all that is happening in your mind.
Although I experience this before, it still happens to me when I take a course and start wondering what am I doing here, this is a waste of time, this is all a cult, a scam, etc. Nope, it's just my mind reacting :) That's how you learn, I don't think there's another way to silence the mind.
I tried to skip a session because I didn't get enough sleep and the management came and got me out of my room.
That's their job. It's not a holiday and you are there to work hard. In fact I can easily say that my first course was the hardest thing I've done in my life, it was just brutal. But my mind felt much clearer, I had way less anxiety and just felt kind of happy.