Diagnostic Nitrox Services — form filling

Address:	Gujarat, Rohtak, Haryana, 124001
Website:	Formfillingwebsite

Was contacted by a person who works for diagnostic nitrox services. They told me that they are offering form filling jobs which pays 25rs per form. I have a target to complete 800 forms with 90% accuracy and if i fail to do so i will have to pay 4, 500 fine. They also provided a user id and password and told me to sign up at: http://www.formfillingworkwebsite.com/Account/Login
I stupidly agreed to a mou (Memorandum o[censored]nderstanding) which i know is not legally binding, but i do worry that it might hold up as a valid agreement in a court of law. I was supposed to start work with them 3rd september 2019, but i asked them a few questions about what kind of forms i am filling to which they replied with a sample form, i further asked them later about their registered address and they just told me the city name not complete address. However they have blocked my user id on the above mentioned website stating that i shouldn't have logged in from some other system as it was against their privacy. After a week they are mailing me and giving me a threat to pay the amount else they will sue me and charge me rs.20, 000.
Please contact me i am being harassed by this company now, and they are threatening legal actions. Please help as soon as possible