There was a question. I posted an answer. I got 3 upvotes and 1 downvote. The OP edited question. After the edit, my answer was useless. So 2 of 3 upvoters removed their upvote. How to deal with those answer-spoilers?
- Downvote the question for being unclear
- Be thankful you even got 10 points for writing that one sentence, that's pretty great points for the amount of effort you put into it in the grand scheme of things.
Other than that, nothing, it's their vote and they can use it however they like. And if the answer no longer answers the quetion, it's definitely not "useful" as the tooltip for the upvote indicates.