Fradualent activities around form filing jobs

15 days back I got call from one online form filling company from Gujarat. They told me that they have vacancy for Virtual assistant contract worker. Lady on the call told me that they will give 15 days online lesson & training & after that I have to give online exam in their website & I have to score 70% passing marks, if failed to do so then I have to pay penalty of 3100 rupees. They were in so hurry to take my consent & they generated an online non disclosure agreement & send me a OTP & asked me to enter that OTP in one form. After that I got email from there side that I have signed digital signature. They also asked for scanned id copy. After that I checked in internet about that company,but that company doesn't exist in MCA registered. Also they 15 day lessons were pathetic. Yesterday I have given exam & there was repetitive questions in their exam & though I have answered all right questions they intentionally failed me. They have give result after 1 hour. Today they are threating me to take legal action if I don't pay them 3100 rupees. I think it is a racket of fraud people who put gun of law to loot money. My surname spelling is also not correct in agreement. Does I am liable to pay them penalty amount??? Does that OTP is digital signature??. Any way to escape from this issue??