it has been a year

i used to be friends with someone on a forum and they started making up lies about me and told everyone they hated me but they never told me why and I am reading old messages from that place from exactly a year ago and they said it's my fault on why they cut themself but I don't really care or feel bad. what do I do because I am still good friends with all of their friends and I am not on that fourm anymore?