I can understand that questions with downvotes or closing votes are closed since they might not meet MSE quality standards.
However, why should "upvoted" questions with upvoted answers be deleted?
Because "upvoted" does not mean "high quality." It means that a few users liked the question, regardless of its quality. Upvotes are not necessarily given as statements on post quality, appropriateness, or as a moderation action - they are more akin to a "like" button.
See, for example, some recent question closures 1, 2 before revision, and 3. All three of these are do-my-problem-without-any-input-from-me posts, and all three deserved a negative response. I just chose these from the list of recently closed questions, and these are all from within the last day.
As far as getting answers back, look for either cached results in Google or look at your "recently deleted" tab on your user page. For example, by Googling the second title you listed in quotes, I found this page with your answer. And FWIW, I strongly agree with the deletion of that question.