Can't Get Possession Of The Flat Even After Registry.

My dad purchased a Flat in March last year. But the previous owner has not given us the possession till date. He keeps delaying. We complained to the police. And there we negotiated that we will sell him back the flat at a settled price. He was about to give us the money by January. But till date he is asking for more time and he is fooling my father. He is not giving us the possession of the flat. The police is not willing to help in the case and has asked us to negotiate personally without registering any case. Please help me with the necessary steps to be taken in this regard. My dad purchased the flat with full receipt and I have all the necessary documents like registry. certificate of possession or naamjari. I have also applied for mutation. Please help me in getting back our money or the flat.