You have said it was a mistake. I do not understand why you could not say "oooops, sorry". An error: Acknowledge it, admit it, apologize for it, oooh, hard part, pay for it, LEARN from it, move on in your life. I gently use the phrase "good help is hard to find" when people are annoyed with me because of things I have left undone, poorly done, etc. and for some reason it seems to help to take the anger away, even if the consequences still need to be dealt with. Good luck to us all.
Tami_hayat