I asked a question here and the first user to answer it deleted their answer with comment:
I have deleted my answer, [since] there was no feedback from you as requested.
I don't remember the entire answer, but it seemed to have useful points for me to research.
This looks like rage deletion to me i.e. revenge for not complying with whatever "requested feedback" he demanded in arbitrary time period he considers "acceptable". And as far as I remember rage/revenge is frowned upon because it gives quite bad impression of Stack Exchange sites to general user. What can be done about such behavior?