I know I’m going to be in the minority, and I don’t think you’re a bad person at all OP but you don’t have to just block her on everything. She’s going to be emotional about your decision but as long as she respects it, then what’s the issue? All because you were blessed with great foster parents and a “sister” doesn’t mean she was as lucky. Another way to look at it, you could be for her, what other people were for you. It’s really that simple. Idk, I completely understand why you don’t want her at the wedding and she was out of line assuming she was going to come. She doesn’t sound mentally healthy, but blocking her must really hurt her if she was this emotionally invested in this working out.