Stn solutions - Stn solutions fraud

As a student i was searching for freelance jobs and got a call from stn solutions. A lady was on the call who provided me a job of filling forms. It was a contract of filling around **** forms with **% accuracy after which they'll pay for the work. They sent an agreement and acceptance letter which was digitally signed. But after completion of the job they judged the accuracy on the basis of spaces between names and even though i had checked the form *-* times before submitting, there were no spaces mistake whatsoever as the names were filled as it was given. now they are demanding money for failure of accuracy as it was on the agreement. But as a student the amount **** is a bit much and what type of job will firstly not pay you for the job after working hard for so many hours and completing the work before the deadline and instead ask you to pay instead. Now they are threatening me and demanding even a higher sum of money by sending notices. Please help i am a student who was just looking for some part time jobs to earn money.