Property paper incomplete and forfeit money

With respect a no brokerage website, we were looking a flat. We met flat owner and after giving token money we asked them to share the property paper. Then he give us few paper and told us rest will be shared during the registery. On the some of documents we make agreement and give them byana and 1 installment and we also chasing for sharing complete papers copy. But they didn't shared. On the second installment we asked them about complete paper and about registery date was near about 1 week. But they asked us they need 15 days more to complete the paper after that they will make paper. We agreed, but again when registery date was near, so asked them about pan card, electric bill water bill and rest proper papers copy to make registery. But they didn't shared us and we asking to return our amount they denied. After a lots conversation we gone to police satiation for complain, but police station person called them and they didn't pick the calls even not our and they also left there house. After that they send us a noticed for that we didn't make registery so they will forfeit our amount. Please advise and suggest.