Agent getting signature from my mother without her consent.

Dear Sir I like to know whether there is any legal case that I can draft against our agent who has cheated my mother by getting her signature on an application form for some purchase of shares in a bogus company called Amrit Projects (NE) Ltd. This company was barred by the SEBI for soliciting money from public in the name of Redeemable Preferential Shares in Aug 2014 which we came to know a few days back. The agent was asked to make 2 FD's of Rs. 50000/ each from SBI Bank in the year 2013. But the agent has possibly kept the paper for purchase of RPS from Amrit Projects for signature below some other FD application forms. Since my mother is not so learned and due to her old age(67yrs) she could not follow what he was making her sign on. After this he returned one FD but said that the other FD certificate is with him which he will give later. But after that 2 years had passed and on several occassions we had politely asked him to give it back but he did not. It is only a few days before when we pressed for it, he showed us the certificate. To our shock we saw that he has invested the money (ofcourse in my mother's name) in this bogus company Amrit Projects (NE) Ltd. for Rs 50000 for purchase of Redeemable Preference Shares. When we asked him to return the principal amount, he told my mother to sign below and said that he will get it prematurely withdrawn. Though the maturity date was Sept. 2016, (Maturity Value-Rs. 70K) she did not mind because signing because she just wanted the principal amount. He told us it will take 7 days time. But today is already the 8th day. I want to know what should be our next course of action. Can we threaten him of some legal action or not. Please help Thanking you Yours faithfully S. Roy Choudhury