Regarding debuts fotcefully imposed

I joined a tour company in 12 January 2015. I was said to be paid rupees 40000.00 per month. However when asking for appointment letter, it was said that it will be given after 3 months (in April 2015). During this course they appointed a corporate sales person through my reference in February 2015. Every month we gave profitable business to the company through our own references and efforts. The company did not support in any means except giving us laptops. This corporate guy sensed something wrong and did not share his business refereces to the company director. Also he did not report properly to the Director. In April when we announced to leave the company and go opening a joint venture of our own. This message came into notice to the director. He closed my offical emai id and asked me to send me mails using my personal email id. One day director suddenly called both of us in office and threatend us to put behind bars saying that we were planning to open our own company. I got scared and asked him to releave me on immidiate basis. He then offered me the option to write a declaration that I will pay one month salary of the corporate sales exevutive (rupees 45000.00). Else he will ruin my career. Please advice how can I get out of this exploitation