I also investigated the possibility of getting severance pay as a previous employer did not renew my contract after three years of service. Unfortunately, as the contract expires every year, I was not entitled to severance pay as my employment wasn't terminated. I, like most teachers, do not have a rolling contract. I went to the department of labour in Lamphun who told me that because the school didn't actually terminate my employment during contract I did not qualify. This is why schools don't give two year or rolling contracts. In addition, the schools can also increase the hours that you work each year without increasing your salary. Why does the expression "white slave trade" come to mind?
So, if you sign a new contract for a second year with an increase in hours and then you do the absolute minimum of work possible to compensate, they school won't sack you because they would rather keep you as a loafer than pay you for not being there. The moral of the story is: if you are in a job/school that you don't like and find it impossible to leave/get another job at the end of the contract, then sign for another year and do as little as you like. Either way, you'll get paid for doing nothing.