Your poor baby!!! I am a groomer and I have to tell you that is not a "nick". It took some serious negligence by the groomer to do that. I seriously can't even imagine how she did it??? The pattern of the cut is so odd I have no clue what she could have been doing to make a cut like that? She shouldn't have been "tipping" the ear that far down? and even if she was it is still an odd looking cut. And then for the owner to treat you that way.
I would definitely go to the local papers with your story! I am sorry you and your baby had such a bad experience.