Personally, if a prof didn't seem excited or pleased to be writing a rec for me I'd go looking for someone else to do it. Sounds like she was not really into it from the beginning. I don't know if you can "undo" a recommendation already sent but I would suggest you get someone new asap. Although it was extremely rude of her to keep you hanging like that and she unfairly put you in a horrible situation, it looks pretty immature on your part that you had your mom call her. After something like that, if I were a prof, I don't think I'd write a good recommendation either.