Using black magic to hurt someone? [Spirituality & Religion]

This girl took advantage of me when I was helping her with her anxiety problems. She took for granted everything I did for her, and part of me wants to "get even". But at the same time I don't really want to hurt them, so I don't know what to do. I dabbled with black magic before to get rid of her abusive boyfriends, I'm thinking I could use it again in this case, but I don't know what to do.