A Transgender pinched me in train.

I am a college student 19M and was travelling to college from home in 3AC coach and a transgender came and asked for money so i handed a 10 rupees coin and they said I won't take this much and demanded for more and when i refused they pinched me near stomach and said that she won't go until I give more. Argued with me for a minute and then fortunately a man came and shouted at them and told to leave. I didn't know what to do in this situation.