Need urgent help

Hi I’m 24, I work in a central government office under an agency. The agency has been extremely abusive by delaying salaries not replacing other personell and just trying to extort money out of my salary as well. I’ve been in this job since Jan of this year, and this has been ongoing for long time. My mental health is so bad because of this. I’m the only full time employee under the agency and there are part timers. The agency pays them on time because they give him commission, I only get 35,000 in Bangalore. I am planning to quit the job, and idk how to do it by receiving my salary for this month and my experience letter. I do not have much money to spend on legal procedures as well. I also feel so vengeful towards him for ruining my mental health and treating me this way. I feel so so isolated and alone. Please help