Yeah what if the website isn't finished? Does the seller still get paid? I really wonder how they plan on solving conditional logic that depends on programmatic

Yeah what if the website isn't finished? Does the seller still get paid? I really wonder how they plan on solving conditional logic that depends on programmatic sources. What happens if you want to change the contract? How do you revoke the previous one? I suppose this would have to be done in a manner that involves both parties, some sort of two part signing process. What if there's a bug in the contract? The contract then becomes ambiguous and you're left with the same problem.