I would recommend that you get someone at your school to find out about the tax and the residency certificate. I went through the same thing where my co insisted that she didn't need my tax forms from South Africa, and then, at the end of Feb, right after a holiday, I was told I was being taxed 300,000. Then my co started running around trying to figure out what to do about the situation when I reminded her I'm not supposed to be taxed. Now, 3 months later, the situation is still not sorted out, that co has left to another school leaving my new co in charge of the mess, and no one at the tax office can answer any of my questions. They honestly seem very confused about the whole situation. As far as I can gather from my other teacher friends, the school is supposed to file your tax info for you, and the admin office should take care of it.