Wrong Plot no. Entered in the my sale deed and now Executant Re-sold the property to someone else

Dear Sir, There was one property (in State: Bihar Distt: Chhapra, Registraion Office: Sonepur) in the name of my grand mother (Now Deceased) which she sold to my mother in the sub registrar office with proper sale deed in 2009 when she was alive and all nominees of my Grand Mother i.e. 1) My elder Aunt (Widow) 2) My Father 3) My other aunt (Widow) and 4) My younger uncle were in consent. But unfortunately the Plot no. entered in the sale deed had written wrong i.e. instead of Plot no. 1647 in sale deed it is written 1645 which belong to someone else. However all the Surrounding (4 Sides) and other details are correct. And as it was a family property and my parents were not well educated about property laws so neither they checked this mistake nor they get the Mutation done. However we were having possession. When my Grand mother died and by luck my cunning uncle and aunts came to know that the plot no. is wrong in sale deed and also there is no mutation done, they all three re-sold the property in our absence to someone else in 2015 who is a muscleman in that area who got the mutation done in his name and took possession of that land forcefully as we were living now in Delhi. Its my humble request to experts to kindly guide me on this scenario that what can be done best to get it in my mothers name or what is the feasibility in this case. Looking forward for an expert guidance. Thanks in advance. Rajesh Kumar Singh