Anna University — regarding my pending salary

I worked as an assistant professor at chennai institute of technology that is affiliated to anna university, chennai. I have joined there on 6th november 2019. The salary allotted
For me is 23, 000 per month. I started working there but they did not
Give me the appointment order and the principal told that they will
Give it when they have to. The situation got worse and i underwent a
Depressed state because of the pressure i experienced there. As they did not give me
The appointment order, i asked them to relive me. They hesitated to
Listen to me and the principal was not ready to meet me even. I got my
Original certificates after begging to return it. I relived on january
4th, 2020. But they did not pay me salary for those two months. Pls help me to get that