Property fraud

My father tried to purchase a flat of worth 21 lakhs for which he paid 17 lakhs and asked for registration but the owner denied and told will refund all amount. She gave cheques of the total amount which bounced and based on that we filed a complaint in district court under section 138. In the process she returned around 7 lakhs and remaining amount is still pending. Court has convicted her and asked to return back the remaining amount with interest. But still there is no response and police is not helping. She is freely roaming and living in the same region. What should we do? We want our money back