Ancestral property unlawfully sold to my unkle by my grandfather.

My grandfather had land of 2.acres which he has got from my great grandfather after he passed away as his share. My father have 2 brothers one younger and one elder. We moved to another city about 10 years ago where the elder unkle also moved to another city. My younger unkle was taking care of whole proprty and grandfather till last year where we never claimed for our share in property till the time grandfather was alive. Few months back my grandfather passed away and my younger unkle has unlawfully got the Bainama of complete property in his wife’s name along with him as a co-applicant buyer. In the bainama There are 2 major points for reference;1.My grandfather claimed that he had some undeclared outstanding for that he is selling his property to Mrs. (X) & Mr. (Y) there is no family relationship disclosure between buyer and seller in deed. 2. It has been sold for 9Lac whether the govt circle rate is 35 Lac mentioned. Should we appeal inThesil for binama cancellation or file suit?