Unknown woman claiming to be my wife what action can I take

Hi Experts, My dad got call from and unknown PCO number on 29 March 2016, where a lady claims herself my wife (I didn’t had any affairs nor I got married to any one secretly), as per her she married me 8 years back and harassed my father to accept her as daughter in law, for which may dad was in shock, as I got married in 2007 and having 5 year old baby. On 3-4/April 2016, my father received a speed posted letter, from a unknown lady and fake address as I and any of my family member do not know any one by that name, in the letter she stated that if you are not accepting her as daughter in law, she will go to media and women organization. Due to this event, all my family members and wife are suspecting me, and my wife has left me since 15 day to her father home, saying until I prove that this is not true she will not be returning to me. I have the original letters with cover and the PCO number Can I log a police complaint against this fake and unknown women and can I get back my wife and child to our regular life Thanks Suresh Yerolkar