O'Reilly, it is very easy to double-post without realising it if the site is running slow. Once you have clicked 'submit', if the screen does not clear immediately, it is then that you click again on 'submit' thinking you must have missed the first time. This results in a double submission. The site's computers recognise that they are identical and remove one and display the other. That way you believe you didn't double-post as you only see one on the screen, but it happens.
If you have only given 11 answers, then it wouldn't take long to go into your profile, click on the tab that says ' Q's I have answered' and look through them for a red sticker on a response that says 'THIS ANSWER IS BANNED'.
Most of us accept this as a fact of life on this site and most of us will have had questions/answers removed for the same reason.