Kd Technology — they are threatening me... give them to money

I register in clickindia and I found a job in a company name KD technology their I have to fill 2200 form in 20 days. I registered them and they said to do signatures and send them a pic through an app known ass Digidocs. I did it. Then after a day, I found that they have sent me an attachment in which there is an agreement I was not knowing about it now i want to leave the job but they are asking for money and they say they will do legal action against me please tell me what to do. They are asking for 7200 rupees that I cant afford what should I do