I don't reply a lot to letters, but this issue particularly bothers me.

It was rude that the cashier didn't speak to you, but I really don't understand what else was wrong with your visit. You don't explain in what ways the other employees were rude to you.

You complain that you "had to listen to Spanish." Um, oh no? Further, you don't know the circumstances of those employees. I really doubt they're bent on "taking over." They're probably decent people who are just trying to make a living. If they even are from Mexico, they are entitled to try and lead a better life in America if they immigrate legally (And you have no evidence to contradict that they have moved here legally). I'm American, but I'm not so condescending that I think that makes me a higher class of human being than someone from another country.