I Tech — fraud Itech captcha home based work and threatening

I was called by a person and said he is from i tech.
New khirdi road aurangabad maharastra and said they are providing online home based captcha entering work and they provide me 10000 captcha which i need to complete with in 10 days with 90% accuracy and then they sent me two links and copy pasted my signature on the agreement and they sent it to my mail. Then i started work even if enter with 100% accuracy they show me in the report that i made miskes and even the work what i have done does not get updated. Then after 15 days a person called me and said that he is from legal department i tech and said i did not complete the given work with 90% accuracy and told me to pay 5000 penality and 3500 for legal charges. And threatening me if i dont pay he will file a case on me. And he is calling me multiple times and threatening me.
So please sir give me a solution