New Property Litigation

Hello, I live in USA and bought a home in Hyderabad in Nov' 2014. I gave power of attorney to my father in law for registration purposes. I paid 17,00,000 out of my pocket (10,00,000 in advance) and availed 68,00,000 loan from Andhra Bank (for a total of Rs. 85,00,000). I took another 7,00,000 loan in USA to pay for property registration and broker fee. The written agreement was the owner will vacate home on day of registration but on day of registration they requested some more time. We gave them 80,00,000 with agreement that 5,00,000 will be paid when home is vactated. Since they did not agree to this, we gave them post-dated checks in lieu of Bank Demand Drafts. Now the owner of the home and her three daughters (and their husbands) are demanding 17,00,000 more for paying income/capital gains tax (was not part of initial agreement) and when I refused they asked for at least 85,000 more. I refused to give this amount either. The owner's husband expired and left the property in her name and is the sole owner. The daughter's also signed witness forms during registration (two daughter's stay in Hyderabad with Husband's while thired daughter stays in Vishakapatnam with her husband). They are now refusing to vacate the home and threatening to do whatever they want. Is it possible to file a cheating case against the owner and broker's at this point? What is the quickest way to force them to vacate the home.