As a former bookie I had a dispute over a bet with a bookie customer years back, I can't remember what it was all about, but I do know that I was well within my rights to refuse payment on his bet. The client completely refused to accept our ruling and as the bet was placed by credit card, he contacted the bank and requested a Charge-back, the bank granted his request and when he found out how easy it was to get a Charge-back, he then Charged-back every bet he had ever placed by CC, thankfully the bank had a Three month limit on Charge-backs but it still amounted to Thousands of Punts at the time.
I pursued it with the banks, credit card companies, the Garda fraud squad and just about any other interested party that I could think of, all to No avail, he got paid back Three months worth of losing bets while keeping his winning bets.
That to me is "The One that got Away" !