Pexiv Company — threatening and unethical behaviour

I applied for a online data entry job which i saw in clickindia.com. Then a women from the company called me and told me about the work. The work was that i have to fill a total of 900 forms in 9 days which will give me a salary of 22300 from which they will deduct 4700 as registration fees. Failure to complete the task or if i do not maintain an accuracy of 90%, then i will have to pay them 4700 rupees. Since the job was within my capability i agreed to do the job. Then the women told me to take a photo of any of my age proof and they sent me an apk of a document software.in the software, she told me to take a selfie and sign a digital signature. She told me it was mandatory for registration process. After this they made a contract agreement with me mentioning the above information. After the registration, she provided me a link of a website with a username and password and told me i have do the task in the website. I began my work and i completed 260 forms in 3 days. But after the 3rd day i was not able to login to the site. I called the helpline numbers which they provided. It was switchoff and then i called the women but she was not responding to my calls and no response to the gmail either. Hence because of them i could not complete the work provided. After the specified date they are sending me sms and gmail to pay the penalty or they will sue me in court and the amount will go on further. I did not respond to their calls. Now they are saying theyare going to send me a legal notice. When i googled about the company after 2 days of my work, there were so many complaints against them about blackmailing and fraudulent activity but i ignored all that. But later i understood it is a fraud company. Can they really sue me? I am worried. Please help me. I was ready to complete the work as per agreement but how can i if they do not make me to complete it.
Name of the lady :-rajvi patel
[protected]
[protected]@gmail.com
Number of advocate (As per them) :-[protected]