Non payment of Interest on the plot booking amount

Location/place: NAGPUR

I had purchased a plot on instalments from a developer based at nagpur in the year 2008. Even after payment of installments he did not bothered to get the papers of the plot cleared from Town planners and other governmental organisation which are mandatory for every developer before getting it registered in the name of the purchaser i.e. me. After 3 long year they told me that they are refunding the money as the papers of the land are not clear even after that they took another 8 months to refund the money that too without interest when i repeatedly asked for interest they stopped taking my calls and when i sent them a letter by registered post they mischieviously returned it without signing on the acknowledgement. As the developers have no longer stay in nagpur and without informing anyone they shifted to Madhya pradesh.