They are obviously trying to withhold the salary and your bonuses and other things due to you for no good reason.
Is there any clause in your contract according to which you will not be paid during vacation time when you did not work because of vacation?
Is that a private or a state-run High School?

Thanks for your timely response,Turnoi. Now, in answer to your two questions:

1) There is NO CLAUSE IN MY CONTRACT according to which I will not be paid during vacation time when I did not work because of vacation. That's why the school couldn't refer to it in order to justify non-payment of my February salary. Instead, the FAO has used a lame excuse to "justify" said non-payment.
2) The school is a state-run High School (of Sichuan province).

I'm now actively seeking another job, and hope to get one that will pay at least enough for me to recoup the 5200 Yuan shortfall in my salary due to the school's blatant dishonesty, by means of a slightly higher salary, 2200 Yuan holiday travel allowance as opposed to zero here, and air fare allowance higher than the 4000 Yuan here(for a two semester contract). What's needed is that I get such a job offer by Mrch 3rd, when I'll have been paid 5200 Yuan, hopefully!Then I'll walk out on the school.
Otherwise, I'll have to stay, and collect my salary until my contract expires at the end of the semester, albeit I'll have been cheated out of 5200 Yuan!
It seems that my contract here isn't worth the paper it's written on!