I play for a pub league and there's 4 people left on the final table, I raised pre with KQ of Diamonds, two others call. The flop comes Jack high with two diamonds, I bet and one calls. Turn comes 9 of diamonds, I bet just short of the other guys stack, he says all in and I call. I show him my flush and he says something like "it's yours - I'm beaten - I can't win" puts his cards over the line face down and brings his hands back. So I think I've won and the dealer deals out the river anyway and it's a 9. He then says "unless I hit one of them!" Takes his cards from behind the line facedown and turns over J9. I thought I'd won this hand but he took the chips. Thoughts please?