Yeah, lying about being abused is SOOO WRONG for sooo many reasons. There are women in this world who are running and fighting for their lives b/c of abuse. What if someone else comes on one of the message boards saying she was abused - how are the moderators and other posters supposed to take her story? People like you are the reason why women are afraid to talk about this subject matter. You are making things bad for those who really experienced this mess. I can't speak for any of the sororities b/c I don't hold membership in any of them, but please take their advice.
First and foremost, look to God and within to find the truth about yourself. You need to be able to look at the real you in the mirror every morning and every night.