Steven ('At the end of my tether' Ajarn Postbox 26th December 2012) I believe that is a common situation in some schools in Thailand. Unfortunately, the schools with the most vacancies are the schools that have some problems with student (and sometimes teacher) motivation and discipline) Bad treatment from the students and/or lack of support from the school administration result in a high teacher attrition rate and vacancies for new job seekers. The school administration and fellow teachers may mean wonders, but be unable to provide much support because they have their share of problems already. The situation may be compounded by teacher agencies that promise all kinds of things (to the teacher and the school), but sometimes don't even pay in time or the full amount promised (or don't pay at all).
Take heart. There ARE schools where student behavior is tolerable - sometimes downright good. It may take a few trials, though, because the odds are definitely against the new teacher.