Oklahoma Land Dispute-14 years Later

If my father, & his 2 nephews own some land in Oklahoma, because their own father died. And, their spouses called my father & stated they have no interest in the land so my father had a quitclaim deed completed & filed in the county & state courthouse that put everything in his name only, plus he gave the spouses some money for their shares at this time as well. This was 14 years ago, the spouses now claim they never remember signing anything & are asking for money from the land & if it ever hits oil. The spouses kids were young back at the time of the deed but are claiming now that that since their father passed away & had no Will made out & their mothers are the ones who signed the deeds, that are entitled to their portion. However their names were never on the land to begin with. just my father, & his 3 nephews. So what to do?? We already explained this was filed 14 years ago. But the nephews children are claiming they never signed away their rights, even if their moms did. But again, they were never on it. My father just passed away & we checked with the courthouse in OK. & everything was in order in which my dad had my name put on everything as sole owner years before he passed. Now WHAT?? HELP