I Solutions — legal notice being sent to me

Website: They do not have a website

Hi, i received call from i solutions saying i should fill in 10, 000 captchas in 10 days and my total payment would be 22, 500 but they wud take 5000 from it as consultancy fees and remaining 18, 500 would be my final take away. There wasn't any payment before hand, so i thot it was safe. They asked me to share my address proof, and also digitally sign a document which looks like an agreement with no proper clauses (Which i saw only after proving my name). They gave me a link to download the apk for doing the online captcha filling. I was given work on my first day, and they have this weird process of showing the status of the work i do only after 6 pm of the next day, and they show 30% of my captcha as wrong (90% accuracy is required in total). The said if i will not be able to complete in the stipulated time, i could ask for extension or else i will have to pay 5000 which i thought would be taken from my salary that they would pay. I complete nearly 5000 captchas but realized that it takes more time in loading the captchas (Even half a day) and most of my captchas are shown as wrong. I stopped working then. On 11th day they revoked my access to the captcha filling application. It is through this same application that i should get my payment and i have to do the transaction. Since they logged me off, if at all i had completed the work i wouldn't get my payment. I dint get payment for the 5000 captchas i had filled. Later i started getting msgs from this bt-arbitr sender, saying legal action will be taken if i don't pay the 5000 rs to the client. Later they again send a letter which looked like a legal notice and stated i have to 5000+3000 (Advocate charges).. I have been getting msgs and mails on the same lines.. Latest mail says i have to pay 12, 850. I don't know for what is this. Since they got that agreement with no proper clause they are warning me. I dint put my signature, they asked me to simple write my name through tht application which i did not know they would use elsewhere. I am here by attaching all the documents and screenshots. Please help.