Mom emotionally cheated me into putting her name in my property

Dear Lawyers, I bought a house in Mumbai at the age of 25 in the year 2005. Although my parents are not legally divorced they parents are separated since 2002. I was extremely young and my mom gave me emotions gyaan of how I can be impulsive and sell the flat if it is in a single name. She also convinced me that after marriage if my husband is not good, he may take advantage of the flat. Plus I was informed by her that the second owner of the flat has no real rights over the flat. She gave me 1 lakh for the then 17 lakh flat. The loan is in my single name. And I have paid emis worth 8 lakhs out of my pocket plus emis worth 8 lakh from the rentals of the house, apart from the down payment I made for the flat which is approx 1.75 Now in 2015 when I decided to sell the flat, my mother is claiming 50% of the property. And refuses to budge. My mother currently lives in my dad's house that he left in 2002. My dad tried to threaten her that he will sell the house that she is living in, in order to give me the money, or the transfer the house in my name but we are told that, it is the matrimonial house and she has 50% right on it. She has always been very cunning and has clearly cheated me through this. Please advice.