But he did cancel the stake. He did just that. All he has to do is say I am not playing for you and thats it. I'm not saying he is right but that's what happened. Where is this rule saying both sides have to agree?
Under this logic anyone who runs a stake for multiple events that has a huge score up front should just say "ending the stake and I'll send you what you are owed" because they can now play on their own money --assuming they want to.
In any agreement there has to be mutual consent to end it. Just because you fuck up doesn't mean the stake is over; the stake is over when you AND your backers say it is over, unless worded otherwise at the outset. Unfortunately, in most instances it's not enough to take a person to court over, but you would certainly win if you did. Take the Sep situation, any of the backers could take him to court as he made an agreement and guaranteed 100% stakeback, the only things stopping someone from doing it is that A) he has no money, and B) its not enough money to be worth the time and court costs.
You're right that they SHOULD want to end it at this point, but it doesn't mean they HAVE to, or he can just end it when he wants and still play the remaining events. The big issue is that he still played in the Main Event, and unless all of his backers agreed to this it's not as open and shut as you are making it out to be.