You wrote a lengthy letter that could have been a lot shorter and communicated the same message. Everything you experienced was consistent. They told you what to expect when you arrived, and everything they did was in accordance with that.

While I think they shut down earlier than I would expect, you know everyone has to go home sometime. Even though I haven't worked retail, boy I like to go home on time. Maybe their clock was off. Maybe you ahould have arrived a bit earlier.

I do hope you hear back from them, but personally I give retail employees some slack when it comes to closing up and getting to leave the store. In any other job, you just leave. It does seem that based on what you said the hours should be posted xx:xx - 9:50pm, if their clock was correct. Did you ask them what time they were using, and compare to your watch?