Losing friends because of rumors

I don’t know if this is bullying or not but i had a friend who kept talking to people. the friend and i dated for a little bit but then we broke up because of an issue. after we broke up he started to go for my friends. One of the friends was a freshman and he was a senior. the freshman told me he liked her and wanted to ask her out. she said no to him and that day his brother texted me saying that he was not gonna be my friend anymore because i “was spreading rumors which i wasn’t” then i called him and he was like yes you did, i dont know what to do because i’m losing friends from this one person.