1) issue legal notice to joint venture parties to refund your 90%payment with interest at 18%pa within period of 15 days .
2) if they fail to refund you will have to move court to recover Rs 24 lakhs with interest .
3) if your agreement mentions cash component ie 30 lakhs then you can seek to recover said amount also .
4) also obtain stay for building of residential project on said land
5) also file criminal complaint of cheating , criminal breach of trust against the joint venture parties
6) you will have to come down to india to file criminal complaint .
7) for civil suit you can give POA to any relative to file suit in this regard