Gift deed

Dear Sir, My father had gifted to me his share in 2008 through an unconditional gift deed and it was a registered gift deed. Before that, his share was given to my sister by way of registered Will. He then cancelled that Will and gifted to me through an unconditional gift deed. Now my father, instigated by my sister is asking me to write it back to him or to my sister, as I am working abroad she has access to my father always. They also filed complaint to RDO claiming that my father was not aware of this transaction, and I got it done through fraud; whereas the truth is otherwise. It was written with his full consent and knowledge and signed before the registrar. According to them, I got it signed through fraud; and I have now become fraudster in front of my relatives and neighbors. RDO office refused to cancel the registered gift deed and my sister is planning to go to court. Is the onus on them to prove that this was done by fraud or the onus on me to prove that this was not done by fraud and it was done legally? Would appreciate your reply. Regards, Alwin Joseph