What are my rights if leased land size differs?

We signed an unregistered mutual agreement with a landlord for leasing 3 acres of agricultural land. As per the agreement, both parties agreed that the lease could not be cancelled for a minimum of 2 years. We also paid ₹1,00,000 as the lease amount for the first year on the day of signing the agreement. However, just 3 hours after signing, we discovered that the actual land size is only 1.7 acres, which does not comply with the agreed-upon 3 acres mentioned in the agreement. We immediately requested to cancel the agreement and asked for a refund, but the landlord refused. He has also started using the land himself. What legal options do we have in this situation? Can we file a legal complaint? Will the law be in our favor considering the misrepresentation? Whose side is the law likely to support?