All I know of is the NIGC. However, as far as I know, there is no formal process to arbitrate a dispute between player and casino. Even if there were such a dispute process, with this lack of evidence, I think your odds would not look good. A good way to make a case would be to tally blackjacks and hands played, or fives and sixes against all cards played, and then have the results analyzed. Regarding the tapping of the table when you have an ace up, I think the dealers do it as a way of saying "good luck," because players tend to slap the table in that situation.