So, in a nutshell: the Bitcoins were sent from an address belonging to the casino and blockchain.info showed the transaction until it was rejected by the network because of insufficient fees.
Edit: see post below ^^
That way, the Bitcoins remain in the casino's original wallet. Now it's up to the casino operators to verify that and, if they're honest, correct the OP's balance on their site or send the Bitcoins again with enough fees. Correct?
Yes, that's correct.