My opponent has got us signed on a sale deed by cheating us.

My deceased father entered into an agreement for construction of a commercial building complex with Opponent No - 1 vide a registered deed in 2006. In this agreement, the Opponent No - 1 got title of 800 sqft area in ground floor and 1082 sqft area in first floor. Opponent No -1 built the building at her own cost and possessed it for last 12 years with all right including right to sale the property. In 2007, my deceased father sold 1082 sqft area of roof in second floor including 'Roof Right' to Opponent No -2 (Husband of Opponent No - 1). My father was paid consideration money properly. In the Agreement Deed and Sale Deed executed by my father in favor of Opponent No - 1 and 2, the 'Plot No' were mistakenly typed incorrect. In 2018, my opponents approached me and my mother (legal heirs of my father) to execute a Deed for Correction to correct the Plot Number. On good faith and good relation, we signed the papers almost without going through the content. After registration, we can realize that actually we have executed a Sale Deed in favor of my opponents and they have altered all the content relative to the original agreement made by my father. They have acquired more land than the land sold by my father. Moreover they have included a portion of land that was sold to somebody else by my father. My opponents have paid no consideration money to us for executing this Sale Deed. Now my questions are - 1) Can our opponents make a sale deed instead of rectification deed, particularly when it was not verbally agreed upon ? 2) Can we take legal action against our opponents for concealing fact and misguiding us ? 3) What will happen to the extra property and property sold to other and now grabbed by our opponents ? 4) Is there any legal procedure by which we can get this Sale Deed cancelled by Court of Law ? 5) What kind of proof do we need to cancel this Sale Deed ?