When I was researching what it was like to work in China, a common complaint I read was that school administrators were forever throwing curve balls. Sometimes you don't even know when the school holidays are until they are upon you. Or someone phones you and tells you that you're expected to be at a meeting or teach a class you knew nothing about. Or you are expected to volunteer your time at some student activity. Or you feel disrespected because you are obviously out of the loop on a lot of things.
The advice that I read and took to heart was, try not to get irritated by any of this. Just go with the flow. Say "no" to demands that you think are unreasonable but otherwise, hey, would it kill you to do some extra-curricular stuff like English Corner? In fact, being friendly and open may well lead to more opportunities. Being stand-offish and prickly will only increase the ESL teacher's feelings of isolation.