Agreement issue

Dear Sir, what is the validity of an agreement. We have some agricultural Land some part of that was of our uncle in that and their relations are not good with us.They sail their part to a property dealer. They want to acquire road side land while in Map their land part was defined. To avoid all dispute after a long fights we decided to sail also our part land to same property dealer. we decided to sail all in 2.66 Crore total. They were quite cleaver and to avoid stamp duty did emotional to our father and do registered agreement just showing value 30 Lac and show giving value 5 Lac. Although a simple notary was written with actual price as 2.66 crore and show given 30 Lac. But at the time they were not able to give installment and then they send notice that we are submitting 25 Lac and do Benama. But we some how we save our land that time. But Now is the problem as by taking that starting 30 Lac we did agreement for some property , but as they did not give installment but we had to do that and we took money on interest. Now it has been passed over 2 Years but as agreement does not cancel nor they did any case but we got stuck as we are paying a lot of interest also. Now we try to take loan from bank on same property on this they did FIR in IPC 420. We Got stuck in all. Please suggest us what should we do ?