GPA cancellation

Dear all, I need Suggestions on a litigation i am facing and though simple but seems pretty complicated I bought a Agriculture land through a GPA holder (Lets call him as A ) in the year 2002 on 31st of a Nov.The GPA was not a registered one and was executed 1992 or so.Anyways got the sale deed executed registered with Sub Regstr Office and Etc done.Accordingly our name came in the record of rights and on every other documents required i suppose.Later got a Agri Loan,Electric connection,drilled bores,plantation and fencing.After 6 to 8 year Things started getting complicated. 1.The principal Owner ( say B ) and A person claiming to b Tenant ( say C ) together filled a RTS appeal in the SDM court challenging MR entry.Grounds were there is a Tribunal Case pending so the MR entry should be canceled.The appeal came to be allowed and the MR entry got canceled and principal owner's name was reentered in the Record of Rights. 2.As soon as the name were reentered in the Record of Right document,the principal owner ( B ) based on his old sale deed say like 30 yrs old one sold the land and created a new sale deed ( in the name of say D ) and got it registered with Sub Registered Office and accordingly based on that sale deed name of D came into Record of Rights.Now they all are trying to disturb my possession and sell of the land to someone else.The principal owner claims that he had canceled the GPA a day before we got the sale deed executed by giving a paper notification in a local news paper. 3.Now i have filled a comprehensive Suit for the of relief of Declrn,Rof R name correction and challenging the sale deed of ' D 'and to be declared them as null and void.Grounds : GPA was in power and our sale deeds were executed based on the Sale agrmnt which took place few years ago even before the owners claim of GPA Cancellation date and is also mentioned on the sale deed with date.Though i don't have anything in written since it was mutual,since i knew the owner and GPA holder from before. 4.The GPA holder is in my support and he never received any notice of cancellation or anything in written or was that brought to his notice either. I wish to know where i stand in all this mess and what are the odds.I have invested loads of money in developing the land and i do have all the documents to prove,the electric connection is in my name etc.Kindly suggest me and shed some lights on the points have mentioned above and the query's down here. : Does a GPA stands canceled only by paper publication.More over it was in only 1 Kannada news paper and the GPA holder's doesn't know Kannada. : Since the GPA was issued way long ago some where in 1992 and later the my sale deeds were executed in 2002,so i am wondering the law/rule to register the GPA existed back then in that year. : Well One more thing i here is even technically if consider GPA still had powers,i am still at fault since there were case/litigation { The Tribunal Case } pending when i bought the land so my purchase is not valid. Thank you all in advance