Andreika doesn't like to cast negative spells because she only hears one side of the story and doesn't want to harm an innocent person. So only if you are certain you are not mistaken, and that a specific person is out to do you wrong, only then will Andreika do your bidding.
But please heed this warning: Andreika's Wicked Revenge spell is a formidable spell that you should think over very carefully before requesting. If you feel there is an individual with bad intent who is causing you to suffer a fate you don't deserve, let it be known that Andreika will treat your situation as if it had happened to her! And heaven help that person. Enough said.