Why would my so called friend tell me that?

A few days ago my friend told me that the guy i liked and her were standing with a group of my friends. My guy friends were talking to the guy i like about another girl liking him, and then my girl friend told the guy i like oh doesnt "cecelia" like you too? and then she said that my guys friends said to my crush ewww gross.why do all the ugly girls like you? and that my crush was like, yeah im not interested.so i got upset and asked one of the people in the group that supposely said that why he said that and he said he would never say that and everyone else in that group would never say that. Why did my friend lie to me and say that so i got upset? My crush has no idea i like him still, but why would she tell me that he does and is not interested?