private college salary

dear sir ,
i am teaching at a private college since July 1, 2008. my appointment letter says my salary will be against 24 lectures per week and i shall be paid for extra lectures. But i have been taking 32 lectures per week and now it is almost 40 lectures per week. i am not being given my salary in time. some time i receive half salary. now i requested my GP fund and pending salaries but not paid. management gives lame excuses. please tell me how can i get my pending salaries, extra class payments and GP fund
thanks
mahmood hayat khan