Earlier today I answered a question titled "About the paper : “Label-Free Supervision of Neural Networks with Physics and Domain Knowledge”", for which I had to check the original paper. I spent some time answering the question but then, half an hour later the user deleted his question and there goes my answer with it. I do not mind getting no votes or getting downvoted, but information being deleted so easily is quite annoying.
My question is, isn't there some kind of restriction on deleting answered questions so easily? If there is not, can I block the user so that I won't spend any more time trying to answer questions from him?