can anyone help with these rules?

so, we playing muggins. Im a point away from being skunked after i have scored my hand. opponent scores hand then crib. before crib, opponent requires 5 points for 121. opponent claims 7 points for crib and moves to finish hole. but the crib actually contains 9 points and i call muggins for 2 points to get me past the skunking threshold. opponent claims i am not entitled to those points as the game is over!?

re: can anyone help with these rules?

Sorry, but you've been skunked in this situation. Once your opponent pegs out, the game is over, and no additional points may be pegged.