Give a detailed representation to the talathi informing him that in 2006, you were handed a 7/12 extract in which you name was duly exhibited and now, after a lapse of more than 10 years, when you applied for a fresh extract you were apprised to know that your name was still not mutated. Request him to go ahead and do the needful without insisting the participation of the seller, for you not aware of the whereabouts of the seller.
In case no decision is taken on your representation or if the needful is not done, approach the High Court and file a writ of mandamus.