fraud done by dealer

i hv done an agreement to sell by a dealer of a floor on dated 30-06-2011 of rs 34.5 lakh.they sold the property without intimation to owner.they took 9 lakh upto 30-10-2012 .they provide me a agreement to sell with false signature of owner ..after that they told they cant do the registary and told us to taken an amount of rs 2100000/- upto 20-01-2013 .and provided a cheque of rs 2100000/- of their company a/c . but on the same dt they told they are not able to pay that amount they will get the registry done..but they dint ..than in the month june 2013,they made a direct agreemnt with owner but they mentioned 41 lakh in that agreement and show only 5 lakh rs as a token amount ..the expiry dt of that agreemnt was aug 2013.but on that day they dint do the registary .finally they gave 25lakh cheque as a gurantee amount on dt 15-04-2013.. now i deposited the cheque.and cheque dishonoured .now they are not giving any response.and selling that property to other. i am very confused what sud i do ? please guide ..